BAGHDAD (AFP) – Baghdad’s heavily fortified Green Zone was hit by two waves of mortar attacks on Sunday that caused no casualties but sent panicked US embassy staff scurrying into bunkers, officials and witnesses said.

In the restive northern city of Mosul, meanwhile, a suicide bomber crashed an explosives-laden truck into an Iraqi army base, sparking a blast that killed 10 soldiers and wounded 30 people, mostly soldiers, an officer said.

The attacks follow a relative lull in the violence in the past few days and come days after the fifth anniversary of the US-led invasion of March 20, 2003, with millions of Iraqis still battling daily chaos and rampant bloodshed.

Black smoke was seen rising from the Green Zone, the seat of the Iraqi government and the US embassy also known as the International Zone, immediately after the 6:30 am (0330 GMT) and 10:30 am (0730 GMT) attacks.

US attack helicopters were also seen circling above the sprawling complex, which once served as Saddam Hussein’s presidential compound.

US embassy officials said there were no immediate reports of casualties while witnesses said some buildings had suffered minor damage and some fires.

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.

A US embassy spokesman confirmed both attacks.

“I heard the blasts. We are checking damage. We have no reports of casualties,” the spokesman said.

He was unable to say whether the mortar rounds landed near the embassy. “All I can say is that they fell in the International Zone.”

An embassy employee, who would not be named, said staff dashed for the embassy’s bunker after both attacks.

“The first attack woke us up and people went rushing to the bunker. It was very frightening. The blasts were very close. Some people were in the showers and arrived with towels around them,” she told AFP.

“Others were nonchalant and carried on as if nothing had happened. This was the worst attack since last summer, when some buildings in the embassy compound were hit by mortars.”

US embassy spokeswoman Mirembe Nantongo told AFP after the first attack that an initial assessment did not indicate any “death or major casualties.”

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.

The Mosul suicide bombing struck around 7 am (0400 GMT), army officer Major Mohammed Ahmed told AFP.

“The bomber smashed the truck through barriers at the entrance to the base and triggered the explosion around ” said Ahmed.

The 10 dead and 25 of the wounded were Iraqi soldiers, while five civilians were also wounded.

Witnesses said Iraqi forces sealed the area surrounding the base, in the Al-Hermat neighbourhood of west Mosul, and prevented anyone entering or leaving.

Military planes and helicopters were seen hovering above the base.

Iraqi and US troops are engaged in a major offensive against Al-Qaeda in Iraq’s main northern city, which according to US commanders is the jihadists’ last urban stronghold in Iraq.

The number of attacks across Iraq has fallen by 60 percent since June, according to US commanders, who warn however that Al-Qaeda remains a dangerous force.