The White House has not made any official moves that would indicate that President Obama will be seeking congressional authorization for military strikes against the Islamic State, leading top Capitol Hill leaders to believe that he will not be asking them for approval to take formal action in Syria, according to senior House and Senate aides in both parties familiar with ongoing talks between Congress and the administration.

Top House Republican aides said Monday night that based on conversations with White House aides, they do not expect Obama to seek formal authorization. Top House GOP leaders also do not expect to be bringing any such legislation to the floor in the coming days, said the aides, who asked to remain anonymous because they weren't authorized to speak publicly on the matter.

The administration's position became apparent Monday, according to a senior Senate Democratic aide, who said that while the situation was fluid, the White House "had not started the formal process" involved in seeking authorization or given any indication that it planned to do so. Another top aide said that based on conversations between leadership and committee staffs, they didn't anticipate a formal request. These aides also sought anonymity because they were not authorized to speak publicly on the discussions.

White House officials asked about those assessments Monday night pointed to Obama's comments in an interview Sunday on NBC's "Meet the Press" where he said that he doesn't believe that he needs congressional authorization "to protect the American people."

Several aides in both parties privately conceded Monday that the process of seeking congressional authority would likely be too complicated, especially just weeks before the midterm elections.

If Obama were to ask for authorization that explicitly rules out using military ground troops in Iraq or Syria, aides said that he ran the risk of having to reverse course if the situation worsens. And seeking an open-ended authorization might prompt criticism from Republicans concerned that Obama is wavering or responding too softly to the threat and from members of both parties wary of "mission creep," aides said.

Several lawmakers signaled Monday that Obama would be acting within his powers as president to continue airstrikes against militants of the Islamic State, the fundamentalist group based in Syria and Iraq, without formal approval. But most did not specify whether those attacks could continue into Syria -- the issue that lies at the heart of the current debate.

"I don't think we need to do it," Sen. Dianne Feinstein (D-Calif.) said when asked whether Congress needed to provide new, formal authority.

Sen. Benjamin Cardin (D-Md.) said it would be better for Obama to have congressional backing, but said it isn't necessary. "We act stronger when we act together," he said.

Sen. Bernie Sanders (I-Vt.), an independent who caucuses with Democrats and was a vocal critic of the Iraq war, said that Obama "has the right" to continue using airstrikes to attack Islamic State targets in Iraq and Syria without congressional approval. "But I am very strongly opposed to the use of ground troops and before ground troops were used, there most certainly has to be a vote," he said.

In a Senate floor speech Monday afternoon, Sen. Ted Cruz (R-Tex.) called for an aggressive military response to the growing threat of the fundamentalist group, but made no mention of using ground troops.

“I don’t believe the American people are one bit reluctant to defend our national security, to defend the lives of fellow Americans,” Cruz said, adding later: “We should concentrate on a coordinated and overwhelming air campaign that has the clear military objective of destroying the capability of ISIS to carry out terror attacks on the United States.”

Others, however, said that Obama would be wrong not to seek congressional input.

"It would show a disregard for the Constitution," Sen. Rand Paul (R-Ky.) told reporters Monday.

"I don't think we should get dragged into another war," said Rep. Thomas Massie (R-Ky.), a libertarian-leaning conservative. "People are tired of it."

And in a weekend interview, Sen. Angus King (I-Maine) said that "there is a responsibility for Congress to take some action in terms of authorization for the president." He said it "is quite a stretch" for the Obama administration to use previous authorizations of military force in Iraq to mount an expanded campaign against the terror group in Syria.

Other democratic senators, including Sens. Tim Kaine (D-Va.) and Christopher Murphy (D-Ct.), have also suggested Obama would need to seek formal authorization to continue the military campaign against the Islamic State.

Two Republican senators also said Monday that U.S. Special Operations forces should be part of an air-and-ground campaign against the Islamic fundamentalist group.

“Air power alone won’t be enough,” Sen. Johnny Isakson (R-Ga.) said in an interview with The Washington Post. “We need to put together a wide-ranging coalition and have our Special Forces support it.

“Special Forces are how we took out Osama bin Laden,” he added. “I would not be reluctant to use them.”

Sen. Lindsey Graham (R-S.C.), in a separate interview, agreed.

“It’s not possible to be successful on the ground without strong American handholding,” Graham said. “What you’d want to do is interject Special Forces into kill-the-leader-type operations.”

Graham and Isakson have long been two of the Senate GOP’s leading hawks on foreign policy.

Paul Kane contributed to this report.