WASHINGTON - The Obama administration is considering a plan to use U.S. military trainers to help increase the capabilities of the Syrian rebels, in a move that would greatly expand the current CIA training being done quietly in Jordan, U.S. officials told the Associated Press on Thursday.

Any training would take place outside Syria, and one possible location would be Jordan.

The talk of expanded military training comes as President Obama appears to have achieved little headway against a wall of skepticism on Capitol Hill.

The officials said that no decision had been made but that discussions were going on at high levels of the government. It comes as the Obama administration prods Congress to authorize limited military strikes against Syrian President Bashar al-Assad's government in retaliation for a deadly Aug. 21 chemical-weapons attack.

The proposal to use the U.S. military to train the rebels - something the administration has resisted through more than two years of civil war - would answer the demands of some lawmakers, including Sen. John McCain (R., Ariz.), to do more to train and equip the Syrian opposition. Obama in June decided to provide lethal aid to the rebels, but so far none of that assistance has gotten to the opposition.

Officials said Thursday that talk about a military training mission has increased but that there have been no specific Pentagon recommendations forwarded to the White House on how big it should be or how many troops it should involve.

The CIA has been training select groups of rebels in Jordan on the use of communications equipment and some weapons provided by Persian Gulf states. The new discussions center on whether the U.S. military should take over the mission so that hundreds or thousands could be trained, rather than just dozens.

The officials spoke on condition of anonymity because they were not authorized to discuss the plan publicly.

Any new training program conducted by the U.S. military would take time to put in place and likely would not begin until after any potential military action had been taken in response to the recent chemical-weapons attack. It would require getting approvals from the host country, finding appropriate locations, getting the right number of personnel in place to conduct the training, and setting up a vetting system to ensure that instruction was not provided to any rebel groups that might not be friendly to the United States.

The Pentagon already has at least 1,000 troops in Jordan, including trainers working with Jordanian forces. The United States left about a dozen fighter jets and a Patriot missile battery there after a recent training exercise.

Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, has told Congress that the U.S. military would be prepared to do more training for the Syria opposition if needed.

In response to questioning Wednesday during a House Foreign Affairs Committee hearing on Syria, Dempsey said he was "mostly supportive of helping the opposition by their development, by their training and equipping, not by becoming their military arm."

He provided more details in a July letter to Sen. Carl Levin (D., Mich.), chairman of the Senate Armed Services Committee.

He said the United States could provide between several hundred and several thousand trainers, with a cost of as much as $500 million a year, depending on how large the training mission became.

The president faces hardening barriers in Congress, where both Republican critics and Democratic allies have voiced deep reservations or flat opposition to his proposal to enter another war in a predominantly Muslim nation after more than a decade of U.S. conflict overseas. Polls show that much of the American public is skeptical, too.

Obama carved out time from his trip to the Group of 20 economic summit in St. Petersburg, Russia, this week to call key lawmakers.

In the House - where prospects for approval appear dimmer than they do in the Senate - Speaker John A. Boehner (R., Ohio) and Majority Leader Eric Cantor (R. Va.) have said they favor strikes but will not pressure other members on what they consider a "conscience vote."

On the Democratic side, "I'm not exactly leading the charge," House Minority Leader Nancy Pelosi told Time magazine. "But I'm supporting the president."

The White House lobbying effort has included direct conversations between Obama or top administration officials and at least 60 senators and at least 125 House members as of Thursday, according to a White House official, who spoke on the condition of anonymity to discuss internal administration operations.

White House officials said they were not concerned about the vote trend in Congress so far. They said Obama, who returns to Washington late Friday, will begin a more public campaign, including perhaps a presidential address, to win support from Congress and the American public for a strike.

This article contains information from the Washington Post.