Updated

The explosion of sectarian violence in Iraq is a blow that may temporarily stall the U.S.-backed effort to form a permanent government there, Secretary of State Condoleezza Rice said Friday.

"Yes, this makes it harder today and perhaps tomorrow," Rice said, "but I'm confident that the Iraqis are devoted to, dedicated to, the formation of a national unity government and I think they will get back to that process very shortly."

She blamed "people who are trying to stoke civil war in Iraq" for provoking the violence as an 11th-hour play to derail political consensus. She named Al Qaeda and terror leader Abu Musab al-Zarqawi as possible suspects but said she does not know for sure.

"It's some force, some party, that wants to destroy the basis for a national unity government," Rice said.

"I'm not going to speculate but it's rarely been Iraqis who talked about civil war. It's usually been outside foreigners, outside foreign forces, that have talked about civil war, like the Al Qaeda forces that are operating there."

Nearly 130 people have died in the violence this week since Wednesday's bombing of one of Shiite Islam's holiest shrines. Religious leaders summoned Iraq's Shiites and Sunnis to joint prayer services Friday amid an extraordinary daytime curfew.

The country's most influential Shiite political leader called for Sunni-Shiite unity as religious figures sought to calm passions and pull the nation from the brink of civil war after two days of deadly reprisal attacks that followed Wednesday's shrine bombing.

Iraqis fear the violence which followed the Samarra attack had pushed the country closer to civil war than at any time since the U.S.-led invasion nearly three years ago.

"This is an extremely hard and extremely delicate moment, obviously, for the Iraqis because there has been a strike against Iraqi unity, I'm quite certain by those who do not want to see a political resolution," Rice said.

The attacks have "obviously heightened sensibilities," among Iraqis, Rice said. "People's nerves are a bit on edge."

She spoke to reporters after a tour of Arab capitals that did not include Baghdad. She said she decided not to visit Iraq on this trip because she did not want to disrupt the ongoing negotiations among Shia, Sunni and Kurdish leaders working to fashion a permanent government.

The largest Sunni Arab bloc in parliament has pulled out of talks with the main Shiite coalition on forming a new government, saying they will not resume negotiations until the government apologizes for the attacks on Sunni mosques and meets other demands.

"There will be undoubtedly some period of time in which it is hard to have a completely unified response to what has happened, because it is very terrible," Rice said.

Rice said she heard concern from Iraq's neighbors this week about a possible spillover of sectarian violence.

"I do think that there's a concern that the sectarian tensions that outsiders are stoking in Iraq, that those same outsiders might try to stoke sectarian tension in other parts of the region," Rice said.

In a teleconference with reporters at the Pentagon on Friday, a U.S. Army brigade commander said the areas of Baghdad in which his troops are operating were calm on and he expressed confidence that sectarian violence would not escalate further.

"It appears as though the people have really listened to the government of Iraq as well as their religious leadership in terms of not allowing this to break down into violent acts," said Col. Jeffrey Snow, commander of the 1st Brigade of the 10th Mountain Division.