A wave of attacks across Iraq on Sunday killed 47 people, while insurgents fired a barrage of mortars at Baghdad's heavily fortified Green Zone, sending US embassy staff scurrying into bunkers. The deadliest attack was in the main northern city of Mosul where a suicide bomber crashed an explosives-laden truck into an Iraqi army base, triggering a blast that killed 10 soldiers and wounded 30 other people, mostly soldiers, army officer Major Mohammed Ahmed told AFP. "The bomber smashed the truck through barriers at the entrance to the base and triggered the explosion" at around 7:00 am (0400 GMT), said Ahmed.
Iraqi and US troops are engaged in a major offensive against Al-Qaeda in Mosul, which according to US commanders is the jihadists' last urban stronghold in Iraq.
In a brutal attack in the south of Baghdad, armed men travelling in three cars opened fire on crowds in a local market in the mixed Zafaraniyah neighbourhood, killing seven people and wounding 16, security and medical officials said.
In another attack in the Iraqi capital, a Katyusha rocket struck a residential building in largely Shiite eastern Al-Kamaliyah neighbourhood, killing at least five people and wounding eight, security officials said.
A car bomb near a bus stop in Baghdad's Shiite Al-Shuala neighbourhood killed five people and wounded eight others, security officials said.
Further north, a roadside bomb near the town of Al-Tuz, 75 kilometres (50 miles) south of Kirkuk, killed four Iraqi army personnel, a medic said.
Elsewhere in Iraq, four people, including a police officer, were killed in shootings, police said.
The violence on Sunday began with a barrage of mortar fire against Baghdad's Green Zone, the seat of the Iraqi government and the US embassy. Two waves of mortar rounds struck the area between 6:30 am (0330 GMT) and 10:30 am. They caused no casualties but sent panicked US embassy staff scurrying into bunkers, officials and witnesses said.
Black smoke was seen rising from the Green Zone and US attack helicopters were seen circling above the sprawling complex, which once served as Saddam Hussein's presidential compound.
An employee in the Green Zone, Mohammed al-Dulaimi, who witnessed the second attack, said eight mortar rounds fell near the US embassy complex and two a little distance away in a residential area. "They caused slight damage and one sparked a fire," Dulaimi told AFP.
An embassy employee, who would not be named, said staff dashed for the embassy's bunker after both attacks.
Insurgents and militiamen regularly fire mortars or rockets at the Green Zone, one of the most secure areas in Baghdad, although the frequency has diminished with a general improvement in security across the country. The US military claims that most mortar rounds or rockets that hit the area are manufactured in Iran and fired by "rogue" elements of radical Shiite cleric Moqtada al-Sadr's Mahdi Army militia.
Meanwhile, Major General Douglas Stone, in charge of detainees in US prisons in Iraq, said more detainees are being released daily than being arrested. He said this was a reversal of the situation from April last year when a "surge" in US troop numbers saw a dramatic increase in the number of people being detained in connection with alleged insurgency operations. The total number of detainees in two US prisons -- Camp Cropper and Camp Bucca -- has decreased from just under 26,000 in April to around 23,000 now, said Stone. "The release rate has overtaken the intake rate as of February," he told reporters on Sunday.