Baghdad (CNN) -- A flurry of attacks erupted across Iraq on Wednesday, authorities said, just two days after the country endured the worst string of assaults this year and stoked fears of intensified sectarian tensions.
A suicide bomber rammed an explosives-laden car into the house of Gen. Tawfeeq Ahmed, chief of police of Tarmiya, about 50 kilometers (more than 30 miles) north of Baghdad. Two people were killed, and seven others were wounded, but the officer was not in the house when it was attacked, and the structure was badly damaged.
Gunmen in the southeastern Baghdad neighborhood of Zafaraniya opened fire at a stationery store, killing one civilian and wounding three others. The area is populated with Sunnis and Shiites.
Seven people were wounded when four roadside bombs exploded in two Kurdish neighborhoods of Kirkuk, an ethnically divided city in northern Iraq. Those injured included three Kurdish security officers and a police officer. There has been longstanding tension in the city among Arab, Kurdish and Turkmen residents.
Three civilians were wounded when a roadside bomb went off in the Adhamiya neighborhood of northeastern Baghdad, a Sunni enclave.
Three mortar rounds landed inside the heavily fortified Green Zone in central Baghdad early Wednesday, but officials did not immediately know of any casualties.
The Green Zone houses Iraqi government offices and the U.S and British embassies.
The latest incidents come just two days after a barrage of attacks across the country killed at least 84 people and wounded more than 250, the deadliest day for Iraqis in 2011.
The actions raised concerns about Sunni-Shiite sectarian tensions, which raged at the height of the Iraqi war in the past decade.
Maj. Gen. Jeffrey Buchanan, the spokesman for U.S. forces in Iraq, said the single largest threat to Iraq's security today comes from Iranian-backed militia groups and the thousands of fighters, cash and weapons under the predominantly Shiite nation's control.
At the Pentagon on Tuesday, Buchanan said these groups now outpace al Qaeda in Iraq, the predominantly Sunni group that once controlled much of the insurgency that terrorized the country.
The continuation of tension comes as all U.S. troops are scheduled to depart from Iraq at year's end.
It is unclear whether Iraq and the United States will decide to keep some of the soldiers in the country as violence persists.
In another development, Iraqi Prime Minister Nuri al-Maliki on Tuesday appointed the current minister of culture, Sadoun al-Dulaimi, to be the country's acting defense minister.
Al-Dulaimi served as Iraq's defense minister in 2005.
This is one of the key ministry positions that had remained vacant in al-Maliki's government since December amid political quarreling. Al-Maliki has been serving as the acting minister for defense, interior and national security.
The Iraqiya bloc, which most Sunnis back, wanted another candidate for the defense ministry, even though al-Dulaimi is a member of the bloc and is a Sunni.
CNN's Joe Sterling contributed to this report.