Surge: At least two U.S. officials have been killed in the ongoing rocket attacks by insurgents on the Green Zone in Baghdad. Two Iraqi guards were also killed at the Iraqi vice president’s office inside the zone:

Extremists lobbed more rockets or mortars against the U.S.-protected Green Zone Friday in Baghdad, with some falling short and killing two guards outside the Iraqi vice president’s office.

Lubna al-Hashemi, the daughter of Sunni Vice President Tariq al-Hashemi, said at least five other guards were injured when rockets or mortars hit the courtyard outside her father’s offices.

She said her father was praying at the time and was not in the offices.

A thick cloud of smoke was seen over the zone Friday shortly after the first rounds hit.

The bombardment of the Green Zone has prompted the State Dept. to issue a warning to U.S. embassy personnel:

“Due to the continuing threat of indirect fire in the International Zone, all personnel are advised to remain under hard cover at all times,” [the warning] says. “Personnel should only move outside of hard cover for essential reasons.”

“Essential outdoor movements should be sharply limited in duration,” the memo says, adding that personal protective equipment “is mandatory for all outside movements.”

“We strongly recommend personnel do not sleep in their trailers,” it goes on to say, offering space inside the Saddam Hussein-era palace that is the embassy’s temporary home as well as room at an as-yet uncompleted new embassy compound and a limited supply of cots.