WASHINGTON — The Obama administration is engaged in a fierce debate over whether to supply weapons to the rebels in Libya, senior officials said on Tuesday, with some fearful that providing arms would deepen American involvement in a civil war and that some fighters may have links to Al Qaeda.

The debate has drawn in the White House, the State Department and the Pentagon, these officials said, and has prompted an urgent call for intelligence about a ragtag band of rebels who are waging a town-by-town battle against Col. Muammar el-Qaddafi, from a base in eastern Libya long suspected of supplying terrorist recruits.

“Al Qaeda in that part of the country is obviously an issue,” a senior official said.

On a day when Libyan forces counterattacked, fears about the rebels surfaced publicly on Capitol Hill on Tuesday when the military commander of NATO, Adm. James G. Stavridis, told a Senate hearing that there were “flickers” in intelligence reports about the presence of Qaeda and Hezbollah members among the anti-Qaddafi forces. No full picture of the opposition has emerged, Admiral Stavridis said. While eastern Libya was the center of Islamist protests in the late 1990s, it is unclear how many groups retain ties to Al Qaeda.

The French government, which has led the international charge against Colonel Qaddafi, has placed mounting pressure on the United States to provide greater assistance to the rebels. The question of how best to support the opposition dominated an international conference about Libya on Tuesday in London.