The United States will not stop its war on terrorism for the Muslim fasting month of Ramadan, national security adviser Condoleezza Rice said Thursday.

Rice, citing the Sept. 11 attacks on the U.S. that killed about 4,800 people, told reporters at a briefing that the United States could not suspend its fight.

"We have no choice but to try to go both to the source of this in Afghanistan and to try root these organizations out wherever we can and we have to get about that business. We can't afford to have a pause," Rice said.

Muslim leaders around the world had been calling on the United States to halt its Afghan bombing effort during Ramadan.

Ramadan, which starts in mid-November this year, is typically a time in which Muslims fast during the day, feast at night and reflect on their relationships with God.

To attack a Muslim country during this traditionally subdued time would be an affront, said Osama el-Baz, a top adviser to Egyptian President Hosni Mubarak. Even Pakistan's President Gen. Pervez Musharraf, a key ally, plead for restraint during Ramadan.

But Defense Secretary Donald Rumsfeld quipped that "the Taliban and Al Qaeda are unlikely to take a holiday."

The U.S. feared a pause in the campaign would give Al Qaeda and its allies time to recover.

"It certainly wouldn't make military sense to afford the Taliban regime, which has been under very considerable pressure in recent times, the opportunity of regrouping, reorganizing during a predictable period of time," said British Minister of Defense Geoffrey Hoon, who met with Rumsfeld earlier this week.

Even if America had backed off, the Taliban's other enemies would not. The rebel Northern Alliance's Washington envoy, Haron Amin, said Wednesday that Ramadan has never stopped his group's war against the Taliban and certainly won't this year.

There are no direct prescriptions in the Quran against fighting during Ramadan — indeed, the holy book exempts soldiers at war and pregnant women from the daytime fasting required of all other adherents.

"Traditionally, there have been wars that have been fought by Arab nations during Ramadan," said Sen. Carl Levin, D-Mich., chairman of the Senate Armed Services Committee.

The 1980-88 Iran-Iraq war that killed or wounded more than a million people never paused for Ramadan. Nor did the 1963-1967 Egyptian engagement in Yemen, when Egypt used mustard gas against Yemeni tribesmen. Egypt and Syria launched the 1973 Arab-Israeli War during Ramadan — one of its Arab sobriquets is "The Ramadan War" — and on the holiest day of the Jewish calendar, Yom Kippur.

"Perhaps we should tell our friends in Egypt that making a big deal of this is inconsistent," said David Schenker of the Washington Institute for Near East Policy, a think-tank that favors some Israeli positions.

The Associated Press contributed to this report.