"Once we get past the immediate repercussions of (Wednesday's) violence, we will see things stabilize again," Robert Ford, political officer at the U.S. Embassy, told CNN.
More than 100 people died Wednesday and Thursday. The violence, which some fear could lead to civil war, interrupted talks between the government and the Sunni Accord Front.
Dozens of Sunni mosques were targeted Thursday in the wake of Wednesday's bombing of the Golden Mosque in Samarra, one of the Shiites' holiest sites.
The Association of Muslim Scholars issued a rare rebuke to Shiite leader Grand Ayatollah Ali Sistani, accusing him of fomenting violence in reaction to the bombing.
Three journalists for the al-Arabiya television network who were kidnapped during the violence in Samarra were found dead Thursday near the city, an official with the Salaheddin Joint Coordination Center told CNN.