Chairman of the Joint Chiefs of Staff, Gen. Joseph Dunford, says he would consider recommending putting U.S. forces with Iraqi troops to fight Islamic State if that would improve the chances of defeating the militants. (Reuters)

President Obama’s most senior national security advisers have recommended measures that would move U.S. troops closer to the front lines in Iraq and Syria, officials said, a sign of mounting White House dissatisfaction with progress against the Islamic State and a renewed Pentagon push to expand military involvement in long-running conflicts overseas.

The debate over the proposed steps, which would for the first time position a limited number of Special Operations forces on the ground in Syria for an extended time and put U.S. advisers closer to the firefights in Iraq, comes as Defense Secretary Ashton B. Carter presses the military to deliver new options for greater military involvement in Iraq, Syria and Afghanistan.

The changes would represent a significant escalation of the American role in Iraq and Syria. They still require formal approval from Obama, who could make a decision as soon as this week and could decide not to alter the current course, said U.S. officials who spoke on the condition of anonymity because the discussions are still ongoing. It’s unclear how many additional troops would be required to implement the changes being considered by the president, but the number for now is likely to be relatively small, these officials said.

The recommendations came at Obama’s request and reflect the president’s and his top advisers’ concern that the battle in Iraq and Syria is largely stalemated and in need of new ideas to generate momentum against Islamic State forces.

The list of options that went to the president was generated by field commanders and vetted by the president’s top national security advisers, including Carter and Secretary of State John F. Kerry, in a series of meetings over the past few weeks.

More costly and ambitious measures, such as no-fly zones or buffer zones that would require tens of thousands of ground troops to effectively protect innocent civilians, did not receive the backing of any of Obama’s top policy advisers. Democratic presidential front-runner Hillary Rodham Clinton has said that she favors a no-fly zone in Syria.

Senior U.S. officials, however, warned that such measures had the potential to put the United States in direct conflict with the Syrian regime and the Russian and Iranian forces backing it.

The recommendations delivered to Obama would not put U.S. forces in a direct combat role. But they reflect a major shift in mission for the Pentagon, where as recently as last year officials were focused on winding down U.S. wars and on emerging threats such as China’s military rise.

These latest deliberations come shortly after the president decided to keep U.S. troops in Afghanistan past 2016, ending his ambition to bring service members home before he leaves office.

Obama chose Carter for the Pentagon’s top job — and dismissed his predecessor — because the president wanted a leader who could push the military to generate better and more creative options in the battle against the Islamic State. For Carter, that has meant negotiating the often conflicting demands of a president who views the threats emanating from places such as Iraq, Syria and Afghanistan as real but remains determined to keep American forces from being pulled too deeply into costly and in­trac­table foreign conflicts.

Helmet camera footage shows a joint U.S.-Kurdish raid that freed about 70 hostages from an Islamic State prison in northern Iraq on Oct. 22, 2015. (Kurdistan Region Security Council)

The recommendations that went to Obama in a memo last week reflect the president’s conflicting impulses. The proposal would put a small number of U.S. advisers on the ground in Syria for the first time since the United States began military operations against the Islamic State last year. The Pentagon has sent small Special Operations teams into Syria for lightning-quick missions several times since the war began in 2011. The newly proposed Special Operations forces would work with moderate Syrian Arab rebels and possibly some Kurdish groups, such as the People’s Protection Units, or YPG, that have scored some recent victories against the Islamic State.

These groups, backed by American air power, are expected to mount a military offensive on Raqqa, the Islamic State’s de facto capital in Syria, in the near future. The push against Raqqa, if it proves effective, would mark a significant setback for the Islamic State, U.S. officials said.

As for the Iraq side of the border, the president’s top advisers have recommended embedding U.S. advisers at the brigade level for specific operations such as the attack to retake Ramadi, a key western Iraqi city that Islamic State forces seized this past spring. Such a move would position U.S. troops, now largely assigned to training bases, closer to the front lines, where they could help Iraqi commanders plan and prosecute the day-to-day fight against the Islamic State in Ramadi.

In both Iraq and Syria, senior officials have also discussed more aggressively targeting Islamic State infrastructure to cripple the group financially. The Islamic State depends on the sale of oil and electricity inside Syria to pay for its military operations. A more aggressive air campaign, however, carries risks of increasing civilian casualties or making an already horrible humanitarian situation worse.

The president first asked for a broader set of options in Iraq and Syria in July when he made a rare visit to the Pentagon to meet with Carter and his top commanders. The meeting came two months after the fall of Ramadi — a time when the White House was more open to the expanded military force than it had been earlier in the campaign.

“What [the Islamic State] did . . . sent a shock through the system,” said Shawn Brimley, a former White House and Pentagon official who is now executive vice president at the Center for a New American Security.

Following that meeting, Carter asked his generals to develop detailed options for Iraq and Syria, and they were forwarded to the president last week.

At the same time, top Pentagon officials were generating new plans for the White House to keep troops in Afghanistan beyond Obama’s presidency. Earlier this month, Obama said 5,500 troops would stay in Afghanistan in 2017 to prosecute counterterrorism operations against the remnants of al-Qaeda and the Islamic State, a major shift from his earlier vow to bring home virtually all American forces before he left office.

Pentagon officials say Carter has presented the White House with more-detailed proposals for responding to the Islamic State than his predecessor, Chuck Hagel.

“Philosophically, he’s always been more forward-leaning about using the military,” said a senior defense official who, like other officials, spoke on the condition of anonymity to comment on internal discussions.

A physicist who was focused largely on managing multibillion-dollar weapons programs, Carter was not responsible for planning combat operations during his previous Pentagon tours. The more active approach being pressed by Carter and his top commanders in Iraq, Syria and Afghanistan carries risks.

The measures proposed by Carter could lead to greater American casualties. Last week, as part of an effort to work with local forces in Iraq, Carter approved a hostage rescue operation there that left one Delta Force soldier dead, the first combat casualty since troops returned to Iraq last year. Following the operation, Carter said he expected that U.S. troops would take part in more raids in the future.

He cited that operation in a Senate hearing on Tuesday. “We won’t hold back from supporting capable partners in opportunistic attacks against ISIL or conducting such missions directly,” Carter said, using an acronym for Islamic State. “Whether by strikes from the air or direct action on the ground.”

Pentagon officials said Carter, like other senior aides, had been convinced of the need for new steps after setbacks such as the fall of Ramadi and the difficulties that U.S. Central Command has faced in finding suitable partners in Syria.

“He recognized that we’ve got to do something different,” the senior defense official said.

The White House declined to comment on the options being considered by Obama.

The biggest problem facing Carter, and Obama, is that the increase in American military commitment would be unlikely to produce any major changes to the political situations in Iraq and Syria that have given rise to the Islamic Sate.

In Iraq, the United States is fighting the Islamic State alongside Shiite militias — some of which are backed by Iran. Just across the border in Syria, Iran-backed Shiite militias are fighting in support of Syrian President Bashar al-Assad, who is barrel-bombing civilians and battling the moderate rebel groups that the United States is supporting.

Obama has said that Assad, who depends on Iranian and Russian military backing for his regime’s survival, must go for there to be any hope of peace.

“If what the White House wants is creative thinking, they need more of a magician than a secretary of defense,” said Stephen Biddle, a professor at George Washington University’s Elliott School of International Affairs and a frequent adviser to the military. “Our interests align with none of our allies in this conflict.”

Russia’s recent airstrikes in support of Assad’s forces for the moment seem likely only to prolong the war and increase the humanitarian crisis in the country. If conditions worsen in Syria, producing even greater flows of refugees headed for Europe, Carter and eventually Obama could feel pressure to further escalate American involvement in the conflict.

A similar dynamic could play out in Afghanistan, where Carter and his commanders advocated forcefully for a larger American presence than Obama initially planned and were able to win the president’s backing. Obama’s plans now call for keeping 9,800 U.S. troops in the country through most of next year before reducing the force to about 5,500 in late 2016 or early 2017.

But the current American force of about 9,800 troops has not been enough to prevent the Taliban from making gains against Afghan army and police forces. Recently, Taliban forces seized the Afghan city of Kunduz for two weeks before Afghan forces, supported by American advisers and air power, were able to take it back.

For Obama and Carter, though, doing something — even if it isn’t enough to generate immediate battlefield victories — may be preferable to the status quo.

As a student of U.S. defense policy, “Ash Carter more than anyone knows that history looks fondly on secretaries who make decisions, whether they’re right decisions or wrong, in a timely manner and give the president good options,” Brimley said. “History looks less kindly on secretaries who have just treaded water.”

Karoun Demirjian in Washington contributed to this report.