Russian President Vladimir Putin and President Obama shake hands before the start of a bilateral meeting at the United Nations headquarters in New York on Monday. (Chip Somodevilla/Pool/EPA)

U.S. officials sought on Monday to play down the scale and significance of Iraq’s expanded security cooperation with Russia and Syria, saying a new intelligence cell launched by American adversaries in Baghdad would have little effect on U.S. operations against the Islamic State.

But the joint endeavor by Iraq, Iran, Russia and Syria, which follows a dramatic Russian military expansion in Syrian President Bashar al-Assad’s heartland on the Mediterranean coast, underscores the limits of Washington’s ability to dictate events on the region’s increasingly crowded battlefields.

The Iraqi government’s announcement of the new intelligence hub took American officials by surprise. Building on Tehran’s extensive military support for forces battling Islamic State militants in Iraq, it appeared to be a response to the U.S.-led, Western-dominated military alliance now struggling to make headway against the group.

U.S. officials said the new cell is housed in a building across from the Iraqi Defense Ministry in Baghdad’s Green Zone and includes small numbers of low- to mid-level security officials from Russia, Syria and Iran. A spokesman for the Iraqi Defense Ministry said the operation will include senior officials from each country.

American officials said the initiative was unlikely to alter the way the United States shares intelligence with the Iraqi government. Close cooperation with Iraq’s military will be essential for the success of the U.S. strategy in Iraq, which relies on sending Iraqi rather than American forces into combat.

Russia’s president blamed foreign intervention in North Africa and the Middle East for creating a terrorist-fueled “anarchy.” (Reuters)

“If we’ve been able to successfully protect our information from the Iranians for the last year, we can continue to do that,” one military official said, speaking on the condition of anonymity to discuss intelligence matters.

He said the United States provides the Iraqi government only with specific information regarding Islamic State operations and targets, which would likely be of limited use to Russia. “We know how to share information with partners who may also be partnered with those we’re not inclined to share information with,” the official said.

Under pressure to demonstrate progress against the Islamic State, Iraqi Prime Minister Haider al-Abadi on Monday praised Russia’s growing security assistance for his government. Russia has expressed concern, as have other countries, that citizens who have joined in the fight in Syria could return home to continue their jihadist activities.

American officials suggested that the timing of the weekend announcement was designed to enhance Russian President Vladi­mir Putin’s credibility as he appeared at the United Nations to denounce the U.S. campaign against the Islamic State, which is stalemated in Iraq and has suffered a series of embarrassing setbacks in Syria.

Speaking before the U.N. General Assembly on Monday, President Obama and Putin traded critiques of their respective foreign policies in addresses that distilled the basic differences in their countries’ approaches to the civil war in Syria. While both leaders are alarmed by the rise of the Islamic State, they disagree on whether Assad should be allowed to remain in power.

U.S. officials are eager to find new ways to weaken the militants’ hold on much of eastern Syria. Over the past week, following the first direct talks between Russian and American defense chiefs in more than a year, there have been hints of increasing American openness to cooperation with Russia against the Islamic State.

“If countries are going to focus on a common enemy, and that’s ISIL, that can be a good and positive thing,” Deputy Secretary of State Antony J. Blinken told CNN on Monday. “If, on the other hand, they’re taking steps to create more sectarian divisions in Iraq or they’re taking steps to prop up the Assad regime in Syria, that’s a bad thing.” ISIL is an acronym for the Islamic State.

Sen. John McCain (R-Ariz.), chairman of the Senate Armed Services Committee and a prominent critic of the administration’s handling of the Islamic State, disagreed. “It’s a dramatic example of the diminution of­ . . . American influence in the region, particularly in Iraq,” he told MSNBC, referring to the establishment of the joint intelligence operation.

Russia has long provided military support to Syria, which gives Moscow a foothold on the Mediterranean. But in recent weeks, Russia has sent fighter jets, tanks, and hundreds of ground forces to several bases on Syria’s northern coast. U.S. officials say that Syrian government pilots are now flying some of those Russian jets and that Moscow is operating surveillance drones over parts of Syria.

Another U.S. military official said Russia appeared to be preparing to send additional equipment, including rocket launchers and artillery pieces, to Syria.

But American officials believe that Putin’s goals, at least for now, are more limited in Iraq. Before the fall of Saddam Hussein, Baghdad had a long record of military partnership with Russia, which Abadi has sought to expand as he drums up support from all quarters.

“We’re not looking at it as a major unsettling type of thing,” the second military official said. Several U.S. officials said they did not believe that Moscow was planning a military buildup in Iraq like that in Syria.

“I think the purpose of this cell is less to produce and share intelligence than it is to put an exclamation point on Mr. Putin’s thesis that anti-ISIL operations must be conducted through ‘existing governments,’ ” said Fred Hof, a former senior State Department official who is now a fellow at the Atlantic Council.

“His aim is to use the threat posed by ISIL to rehabilitate his client: the same Bashar al-Assad whose policies of collective punishment and mass murder created the vacuum that ISIL now fills in eastern Syria,” Hof said.

Loveday Morris and Mustafa Salim in Baghdad and Karen DeYoung at the United Nations contributed to this report.