In a separate statement, the US military said a fifth soldier had been killed by small arms fire while on foot patrol southeast of Baghdad on Saturday.
Also on Sunday, al-Maliki said a much-anticipated summit to try to end political deadlock among the country's leader could begin in the next two days.
The politicians at the meeting are expected to include al-Maliki; Talabani; Tareq al-Hashemi, the Sunni Arab vice-president; Massoud Barzani the Kurdish regional leader; and Abul Aziz al-Hakim, the SIIC leader.
Al-Maliki, whose national unity government has been in crisis since the main Sunni Arab bloc pulled out, said he would either lure it back or find other Sunni Arabs to replace it.
He said: "The first meeting may happen tomorrow or the day after tomorrow."
Nearly half of the cabinet is no longer participating in its meetings.
Besides the Sunni Arabs, supporters of al-Sadr also quit the government, while the secularist bloc of Iyad Allawi, the former interim prime minister, is boycotting cabinet meetings.
But the head of the Iraqi Accordance Front issued a desperate appeal on Sunday for Arab states to help stop what he called an "unprecedented genocide campaign" by Shia militias armed, trained and controlled by Iran.
Adnan al-Dulaimi said "Persians" and "Safawis", Sunni terms for Iranian Shia, were on the brink of total control in Baghdad and soon would be threatening other Sunni Arab governments.
"It is a war that has started in Baghdad and they will not stop there but will expand it to all Arab lands," he said in an email to the AP news agency.