U.S. bombs pounded Afghanistan for a 12th day on Thursday in fierce strikes that the Pentagon said were apparently driving some of Osama bin Laden's al Qaeda guerrillas from cover and into American bombsights. 
Defense Secretary Donald Rumsfeld said "snippets of intelligence" suggested recent intense strikes by 100 warplanes were making the Saudi-born fugitive's network vulnerable and causing military defections from Afghanistan's ruling Taliban. 
At the same time, U.S. sources told Reuters privately that members of al Qaeda were killed in the U.S. military operations, but there was no evidence that bin Laden or his top lieutenants were among them. 
"We are seeing some people ... starting to decide that they would prefer not to be part of Taliban. And we have seen some movement of what we believe to be the al Qaeda forces -- and they have been specifically targeted while they were moving," Rumsfeld told a Pentagon news conference. 
He added later there was evidence that Taliban and al Qaeda fighters were hiding in mosques and using populated civilian areas for command and control headquarters, and gathering sites. 
"They know that we are a country that tries to avoid high collateral damage targets," Rumsfeld said. "So they do take advantage of that. In fact, we see snippets of information where they are saying that." 
Rumsfeld spoke as U.S. warplanes continued hammering military targets of the Taliban around the capital Kabul, the Taliban stronghold of Kandahar and guerrilla training bases. 
The Taliban have refused to surrender bin Laden, accused by Washington of masterminding Sept. 11 attacks on America. 
Asked about reports from London, Rumsfeld said it was possible a senior al Qaeda official was killed. But he said he could not confirm it. 
An Islamic organization in London reported that the bombing had killed a veteran al Qaeda fighter and associate of bin Laden from Egypt. If true, the death would be the first reported for an important member of the bin Laden network. 
But U.S. sources, who spoke on condition of anonymity, told Reuters there is no evidence that bin Laden or his top lieutenants, Ayman Zawahri, Muhammad Atif, and Abu Zubaydah, were dead. 
"There have been some al Qaeda members who have died," since the U.S. bombing campaign started on Oct. 7," one official said. 
Aside from members of al Qaeda, U.S. officials have said previously that two family members of Taliban leader Mullah Mohammad Omar were killed on the first night of raids. 
Rumsfeld and Air Force Gen. Richard Myers, chairman of the military Joint Chiefs of Staff, refused on Thursday to say when U.S. Special Operations ground troops might join the war. 
AID FOR TALIBAN OPPONENTS? 
Rumsfeld told reporters later with visiting Italian Defense Minister Antonio Martino that the United States would like to be helpful with food, ammunition, and supplies to Taliban opposition groups such as the Northern Alliance and to receive targeting information from them. 
He declined to say whether weapons were already being supplied to their forces, indicating that the issue was politically sensitive. 
Military officials told Reuters on Wednesday that elite special forces were poised on the aircraft carrier USS Kitty Hawk in the Indian Ocean for possible deployment into Afghanistan against a weakened Taliban and al Qaeda. But they cautioned against speculation about any quick move. 
Myers said only that the Pentagon planned to use all available military assets in one of the most significant challenges for the U.S. military since World War Two. 
Myers confirmed that Air Force F-15E jets based in the region were used for the first time in the campaign on Wednesday, striking Taliban troops and armor protecting the key northern city of Mazar-i-Sharif. Other defense officials said the jets were based in Kuwait.