(dpa) - Mortar shells pounded the Green Zone and other areas in Baghdad Wednesday, killing at least eight people and injuring 25, including three US nationals.
Meanwhile, the Iraqi government gave Shiite fighters involved in heavy clashes with its troops in Basra a three-day deadline to hand in their arms.
"Three mortar shells fell Wednesday morning on the Green Zone," a witness in the zone told the Voices of Iraq (VOI) news agency.
Another witness told the agency that another mortar shell fell on a building opposite the Iraqi Foreign Ministry in the Green Zone, killing a civilian and injuring four others.
Three US nationals were seriously injured in the mortar attacks, according to media reports.
The Green Zone is home to the US embassy, other diplomatic missions, Iraq's cabinet, parliament and many ministries.
The area has come under fire from barrages of rockets and mortar shells this week, which US officials blame on suspected Shiite militants.
Also in Baghdad, at least seven people were killed and 18 injured by mortar shells in separate attacks on Risala district, south-west of Baghdad, and Karrada in the centre of the Iraqi capital, police sources were quoted as saying by VOI.
In another development, the Iraqi government gave Shiite fighters in Basra 72 hours to hand in their arms, the Dubai-based al-Arabiya television reported.
Clashes between Iraqi security forces and Shiite fighters in Basra raged Wednesday for the second day, leaving at least 40 people dead and 200 wounded.
Nearly 30,000 Iraqi soldiers and police officers are involved in the operation, which is being directed by Iraqi Prime Minister Nuri al-Maliki, who is also the general commander of the armed forces, according to media reports.
Iraqi troops backed by helicopters have engaged in pitched battles with Shiite fighters since the early hours of Wednesday in many parts of Basra, witnesses told Deutsche Presse-Agentur dpa.
Life in the city has come to a standstill with shops and markets closing and power cuts throwing it into darkness, the witnesses said.
Basra, which until 2005 enjoyed relative peace, has been overrun by rival Shiite militias, mainly the al-Mahdi Army, Badr Organization and another militia controlled by the Islamic Fadila Party.
The al-Mahdi Army, which is loyal to radical cleric Moqtada al- Sadr, is pitted against the Badr Organization, the military wing of the Supreme Islamic Iraqi Council, and the Fadila militia.
Although the government said the offensive was to root out "outlaws" in the city, the al-Mahdi Army said its members and strongholds were being targeted.
"Iraqi troops are now shelling homes and residential areas. There are many martyrs and innocent people killed in Basra," Asma al- Musawi, a member of the al-Sadr Bloc, told dpa.
"The government, which we gave our confidence, popular support and advice, is mounting the biggest operation of targeting, killing and arresting the members of al-Sadr Bloc," she said.
In Baghdad's Sadr City neighbourhood, fighting broke out between Iraqi troops backed by US air support and al-Mahdi Army fighters, killing at least 15 people and injuring 100, al-Arabyia television reported.
US helicopters, taking part in an operation in Sadr City, targeted areas north of the district, Colonel Steve Stover from the multinational forces told VOI.