Iraqi police say gunmen have attacked a mosque near the town of Tikrit, north of Baghdad, killing four Sunni Arab worshippers.
The attack, launched during Muslim prayer hours early Thursday, also wounded at least 13 people.
To the south, in Karbala, local officials say U.S. troops have arrested the sheikh Akeel al-Zubaidi who heads Karbala's provincial council, a mainly Shi'ite group. There has been no report on the incident by U.S. military officials.
Iraq's national security adviser Mowaffaq al-Rubaie told reporters in Baghdad today that last week's killing of Abu Musab al-Zarqawi signals "the beginning of the end" of the terrorist group known as "al-Qaida in Iraq."
The government official says documents found at Zarqawi's hideout have provided valuable information, and Iraqi and coalition forces are pressing an offensive against the terror group.
Baghdad itself is still in the midst of a major security crackdown that was set in motion following President Bush's visit to Iraq this week. Tens of thousands of Iraqi and U.S.-led coalition troops are deployed across the city, in what Prime Minister Nouri al-Maliki says is an effort to stem daily carnage in the capital.
Mr, Maliki has ordered extended curfews and a ban on vehicle traffic during Friday prayer hours - a time when insurgents have launched many attacks. He says he is ready to hold talks with insurgent groups that are prepared to join the political process, but will not negotiate with people who have blood on their hands.
Some information for this report was provided by AFP, AP and Reuters.