Pentagon officials said Wednesday that the Obama administration has ordered additional U.S. troops to Jordan for possible chemical weapons control, humanitarian response or “stability operations” in Syria.

The new troops, a headquarters element of the 1st Armored Division based at Fort Bliss, Tex., will not greatly increase the number of U.S. forces in Jordan. About 150 troops were sent last year to help train Jordanian military and Syrian opposition forces. Some of those troops will remain, and the new arrivals will increase the total to more than 200.

But the dispatch of a headquarters unit indicates a higher level of preparation for a possible expanded U.S. military role, including command and control capability for a larger force.

Defense Secretary Chuck Hagel told Congress that he authorized the deployment last week to “improve readiness and prepare for a number of scenarios.”

Both Hagel and Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, made clear in testimony before the Senate Armed Services Committee that President Obama has not ordered any U.S. military intervention in Syria.

“We don’t have a consensus on this issue . . . on what America’s role should be,” Hagel said.

Numerous lawmakers have pressed the administration to take more aggressive steps to intervene in the two-year-old civil war in Syria. But Hagel said, “Military intervention at this point could hinder humanitarian relief operations. It could embroil the United States in a significant, lengthy and uncertain commitment.”

The remark drew derision from Sen. John McCain (R-Ariz.), who has advocated increased U.S. military support for Syrian rebels, as has Sen. Carl Levin (D-Mich.), the committee’s chairman.

Dempsey said the military was prepared, if asked, to protect rebel-­controlled buffer zones inside Syria near the Jordanian and Turkish borders and establish no-fly zones over those borders. He said planning included various scenarios in the event that President Bashar al-Assad’s government uses chemical weapons.

Asked whether U.S. troops would be used to secure Syria’s chemical weapons, Dempsey said it depended on whether rebel forces were capable of controlling the sites, which are dispersed across the country.

“If we had to go in there, it would be non-permissive,” he said, meaning that U.S. forces would have to defend themselves. “If it was a hostile environment, it would be a significant intervention.”

The deteriorating situation in Syria, where more than 70,000 people have died and millions have been displaced, appears to be pushing the administration closer to a decision. But a high level of uncertainty and disagreement over what to do was reflected in the contentious hearing Wednesday.

Dempsey testified several months ago that he agreed with senior national security officials who recommended arming the rebel military force. When asked by McCain whether he would still make that recommendation, Dempsey said the situation was “more complicated now.”

“My military judgment is that now that we’ve seen the emergence of al-Nusra and Ahrar al-Sham, and seen photos of weapons in the hands of those groups, I’m more concerned than I was before,” he said, referring to leading rebel factions that espouse extreme Islamist goals and have been linked to al-Qaeda by the U.S. government.

“If we could clearly identify the right people, I would support it,” Dempsey said.

But both Dempsey and Hagel said cohesion within the Syrian opposition has decreased in recent months, making military support more risky.

Hagel said he was traveling to the Middle East this weekend to consult with allies in the region on the Syrian conflict.

In testimony before a House committee Wednesday, Secretary of State John F. Kerry said some decisions would be made at a meeting with international partners and leaders of the Syrian political opposition that he will attend in Istanbul on Saturday.

“The fact is that some people are providing weapons . . . and others are apparently about to decide to, some of our friends,” Kerry said. “The United States policy right now is that we are not providing lethal aid, but we are coordinating very, very closely with those who are and with our core group allies.”