Iraq's top Shiite cleric urged all of its people today to unite and expel Sunni Muslim insurgents, as Shiite Prime Minister Nuri al-Maliki came under growing pressure at home and abroad.
The call came after US President Barack Obama stopped short of acceding to Maliki's appeal for air strikes on the Islamic State of Iraq and the Levant (ISIL), prompting neighbouring Shiite Iran to charge that Washington lacked the "will" to fight terror.
A swift militant offensive, led by the jihadist ISIL, has overrun swathes of northern and central Iraq, threatening the United States's already damaged legacy in the country.
Grand Ayatollah Ali al-Sistani, a revered cleric whose stature dwarfs that of any other figure among the Shiite majority, called for Iraqis to band together against the insurgents before it was too late.
If ISIL is not "fought and expelled from Iraq, everyone will regret it tomorrow, when regret has no meaning," his spokesman announced on his behalf.
The reclusive Sistani, who heads a council of senior clerics, also said Iraq's next government must be "effective" and avoid "past mistakes", an apparent rebuke to Maliki, premier since 2006.
His remarks came after several senior American figures pushed the premier, who is seeking to retain his post after winning a plurality in April 30 elections, to work with Iraq's Sunni Arab and Kurdish minorities.
US Vice President Joe Biden, Defence Secretary Chuck Hagel, Chairman of the Joint Chiefs General Martin Dempsey and David Petraeus, the former top US commander in Iraq, have all either called for Maliki to be more inclusive or outright criticised him.
Obama said yesterday Maliki's actions could dictate the country's fate, amid a growing feeling in Washington that the Iraqi leader would do best by moving on.
Iraqi security forces continued to battle militants in several areas today, with 34 members of the security forces killed in a town on the border with Syria.
Elsewhere, the battle for the strategic northern town of Tal Afar entered its sixth day. Witnesses said security forces clashed with militants, who still hold significant ground.
Shiite-majority Tal Afar is located along a strategic corridor to Syria, and the largest town not to fall to militants in the northern province of Nineveh, most of which has been overrun.
A senior army officer told AFP that Iraq needs US help.
"We need American support to stop terrorism and eliminate it... Especially through air strikes against specific targets," the lieutenant general said, asking not to be identified.
