An array of Iran-backed Iraqi militia groups have agreed to suspend rocket attacks on U.S. forces on the condition that Iraq's government present a timetable for a withdrawal of American troops, one of the groups said on Sunday.

"The factions have presented a conditional ceasefire," said Mohammed Mohi, spokesman for the Iran-backed Kataib Hezbollah group.

"It includes all factions of the (anti-U.S.) resistance, including those who have been targeting U.S. forces," he told Reuters.