Baghdad, Iraq ? Insurgents fired at least seven rockets Sunday night on the U.S. coalition headquarters in Baghdad, hitting a hotel used by U.S. occupation officials and wounding one American, the military said. It was the biggest attack on the Green Zone in weeks.

A series of explosions echoed across central Baghdad from the strike, sirens blared, and smoke and flames were briefly visible in the Green Zone, the heavily guarded area where the U.S.-led coalition is based.

Five rockets hit the Al-Rasheed hotel, where some civilian contractors live. A U.S. civilian contractor was wounded, the military said.

The Al-Rasheed is across the street from the Baghdad Convention Center, where Iraq’s Governing Council plans to sign an interim constitution today.

Shiite Muslim political leaders who had refused Friday to sign the document said Sunday that they would approve it without changes despite concerns voiced by the country’s top cleric.

The Shiite politicians agreed to change their position after meeting with the cleric, Grand Ayatollah Ali Sistani, in Najaf.

In refusing to sign the document on Friday, the politicians said that Sistani had rejected two provisions in the interim constitution, one that would give ethnic Kurds, who make up 20 percent of Iraq’s population, effective veto power over a permanent constitution and another that would establish a single president under the transitional administration.

After Sunday’s meeting, a top aide to one of the political leaders said Sistani was still not happy with the provisions but would not order the politicians to reject the document.

Smoke billows behind the former Presidential Palace of toppled Iraqi dictator Saddam Hussein in the Green Zone, a base for coalition forces and civilian personnel. Insurgents fired at least seven rockets on the area Sunday.