Fighting between rival Iraqi forces raged for a second day Tuesday as the death toll from violence sparked by Iraqi cleric Moqtada al-Sadr’s resignation from politics mounted to 23, according to medical sources. The violence prompted Iran to close its air and land borders with Iraq just as millions of Iranians were preparing for an annual pilgrimage to Shiite sites.

Tensions have soared in Iraq amid a political crisis that has left the country without a new government, prime minister or president for months, and escalated sharply after Sadr's supporters on Monday stormed the government palace following the Shiite cleric's announcement that he was quitting politics.

The violence pitched Sadr's supporters against rival Shiite factions backed by neighbouring Iran.

Overnight, shelling targeted the high-security Green Zone that houses government buildings and diplomatic missions amid angry protests after Sadr's surprise announcement. Footage posted on social media on Tuesday morning showed militia members firing their weapons into the Green Zone as the unrest mounted.

Witnesses said Sadr loyalists and supporters of a rival Shiite bloc, the pro-Iran Coordination Framework, exchanged fire.

A security source told the AFP that Sadr's supporters opened fire at the Green Zone from the outside, adding security forces inside "were not responding".

After a lull in violence late Monday, fresh clashes between Sadr's supporters and the army and men of the Hashed al-Shaabi, former Tehran-backed paramilitaries integrated into the Iraqi forces, erupted again on Tuesday morning.

Medics on Tuesday updated the toll of Sadr supporters killed to 23, with some 380 others injured – some with bullet wounds and others suffering tear gas inhalation.

The rattle of automatic gunfire and heavier explosions of rocket-propelled grenades could be heard from the Green Zone, according to reporters and witnesses in the area.

Survival of state 'at stake' 

The UN in Iraq has warned of "an extremely dangerous escalation" and called on all sides to "refrain from acts that could lead to an unstoppable chain of events".

"The very survival of the state is at stake," the UN warned.

The US also urged calm amid the "disturbing" reports, while France called on "the parties to exercise the utmost restraint".

Iraq's caretaker Prime Minister Mustafa al-Kadhimi said "security or military forces, or armed men" were prohibited from opening fire on protesters.

The country's military on Monday announced a nationwide curfew, and Kadhimi suspended cabinet sessions in response to the violence. 

Iran closes border to Iraq

Iran closed its land borders to Iraq and Iranian flights to the country halted Tuesday as the violence mounted, with no resolution in sight to Iraq's political crisis.

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.

His refusal to negotiate with his Iran-backed Shiite rivals and subsequent exit from talks has catapulted the country into political uncertainty and volatility amid intensifying intra-Shiite wrangling.

To further his political interests, Sadr has wrapped his rhetoric in a nationalist and reform agenda that resonates powerfully among his broad grassroots base of supporters. They are calling for the dissolution of parliament and early elections without the participation of Iran-backed Shiite groups, which they see as responsible for the status quo.

Sadr's latest announcement came as millions of Iranians were preparing to visit Iraq for the annual pilgrimage to Shiite sites.

Kuwait meanwhile has urged its citizens in neighboring Iraq to leave the country. The state-run KUNA news agency also encouraged those hoping to travel to Iraq to delay their plans over the eruption of violent street clashes between rival Shiite groups in the country. 

The tiny Gulf Arab sheikhdom of Kuwait shares a 254-kilometre (158 mile) long border with Iraq.

Dubai's long-haul carrier Emirates stopped flights to Baghdad on Tuesday over the ongoing unrest in Iraq. The carrier said that it was “monitoring the situation closely”.

It did not say whether flights would resume for Wednesday.

(FRANCE 24 with AFP and AP)