Iraqi generals said early on Sunday that troops backed by a Shiite militia had retaken some areas after the past week's dramatic gains by insurgents in the Sunni heartland north of Baghdad.

A spokesman for Iraqi army command, Major-General Qassim al-Moussawi said government forces had "regained the initiative" in the north and northeast and would "not stop from liberating" areas, including Mosul.

It was overrun last Tuesday by the militant group calling itself the Islamic State in Iraq and Levant and known by the acronym ISIS, which wants to revive a medieval caliphate that would span parts of Syria and Iraq.

The Iraqi military said the towns retaken were near Samarra, a declared target of the insurgent ISIS, which was visited by Prime Minister Nouri al-Maliki on Friday.

Volunteers answer call

On Saturday, Shiite volunteers from across southern and central Iraq flocked to Baghdad before heading to a base just north of capital to undergo basic training (pictured above). The call to arms to protect shrines came from top Shiite cleric, Ayatollah Ali al-Sistani.

An offer of help to Baghdad from the president of neighboring Shiite Iran, Hassan Rouhani, drew a cautious response from Iraqi premier Maliki, who said "talk of Sunnis and Shiites must be dropped."

All Iraq is on your side," he said in addressing army personnel. "The recruitment centres are teeming with volunteers."

Critics of Maliki, who has been in power since 2006, accuse him of monopolizing power and manipulating his so-called campaign against terrorism to marginalize Iraq's Sunni minority.

Iran retains close ties with Maliki's government in the wake of the 2003 US-led invasion of Iraq and subsequent troop withdrawal in 2011.

End divisions, urges Kerry

From Washington, US Secretary of State John Kerry said assistance from the US would only work if Iraqi leaders overcame deep divisions.

His remarks came as the US moved an aircraft carrier naval group from the northern Arabian Sea into the Gulf, closer to Iraq.

The US State Department said Kerry had spoken with Iraqi Foreign Minister Hoshyar Zebari and called for national unity based on the ratification of recent election results and formation of a new government.

Blair denies invasion impact

Former British premier Tony Blair hit out on Sunday against critics who attribute Iraq's current turmoil to the 2003 US-led invasion backed by Britain that removed the-then Sunni strongman Saddam Hussain.

In a long article on his website, Blair instead blamed Iraq's situation on the West's failure to act in Syria.

Three years of civil-war in Syria had provided Islamist militants with battle experience and a base from which to launch their attacks into Iraq, Blair said.

"The choices are all pretty ugly, it is true. But for three years we have watched Syria descend into the abyss and as it is going down, it is slowly but surely wrapping its cords around us pulling us down with it," he said.

Blair is currently the representative for the so-called Middle East Quartet, comprising the UN, the EU, the US and Russia.

ipj/jlw (Reuters, AFP, dpa, AP)