Baghdad, Iraq ? Top U.S. military and civilian officials were at odds Thursday over the role of foreign fighters in this week’s savage bombings at Shiite Muslim religious shrines — acts of violence that raised the specter of sectarian war.

U.S. administrator L. Paul Bremer said it was “increasingly apparent” terrorism was coming from outside Iraq, but some American generals were far less certain about the extent of the foreign role.

The brutal sophistication of Tuesday’s bombings in Karbala and Baghdad pointed to a foreign influence on an insurgency that is still mainly homegrown, said Brig. Gen. Martin Dempsey, commander of the 1st Armored Division, which controls Baghdad.

“It’s far more than a supposition and far less than empirical evidence” to say Abu Musab al-Zarqawi, a suspected anti-U.S. militant with ties to al-Qaida, had a hand in the Tuesday blasts, Dempsey said. “It’s a very educated guess.”

He called the idea that foreign fighters were flooding Iraq “a misconception.”

Another military official in Baghdad, who asked not to be named, said intelligence “strongly suggests” al-Zarqawi was behind the blasts Tuesday, the bloodiest day since Saddam Hussein’s regime collapsed.

The Iraqi Governing Council said 271 people were killed in the attacks; the U.S. coalition said 181 people were killed and 573 wounded.

Al-Zarqawi emerged as the top suspect within hours of the bombings.

Bremer and members of the Governing Council took turns blaming the Jordanian fugitive, the alleged author of a letter calling for a civil war fueled by attacks on Iraq’s majority Shiites.

An Iraqi lights candles Thursday after placing flowers by the side door of Kazimiya Shrine, which was damaged by Tuesday's coordinated suicide attacks in Baghdad, Iraq. Tuesday's attacks in Baghdad and the holy city of Karbala, which killed more than 100 people and injured hundreds more, were the bloodiest carried out in Iraq since the fall of Saddam Hussein.