BAGHDAD — 

Supporters of an influential Iraqi Shiite cleric fired rocket-propelled grenades and machine gun bullets into Iraq’s Green Zone and security forces returned fire Tuesday, in a serious escalation of a months-long political crisis gripping the nation.

The death toll rose to at least 30 people after two days of unrest, officials said.

After cleric Muqtada Sadr announced Monday that he would resign from politics, his supporters stormed the Green Zone, once the stronghold of the U.S. military and now home to Iraqi government offices and foreign embassies. At least one country evacuated its embassy amid the chaos.

Iraq’s government has been deadlocked since Sadr’s party won the largest share of seats in October parliamentary elections but not enough to secure a majority government — unleashing months of infighting between different Shiite factions. Sadr refused to negotiate with his Iran-backed Shiite rivals, and his withdrawal Monday catapulted Iraq into political uncertainty and volatility with no clear path out.

Iran closed its borders to Iraq on Tuesday — a sign of Tehran’s concern that the chaos could spread, though streets beyond the capital’s government quarter largely remained calm. The country’s vital oil continued to flow, with global benchmark Brent crude trading slightly down at $103 a barrel.

A day after they stormed the Green Zone, supporters of Sadr could be seen on live television firing both heavy machine guns and rocket-propelled grenades into the heavily fortified area through a section of pulled-down concrete walls. Security forces armed with machine guns inside the zone sporadically returned fire.