After a wave of attacks on the US embassy in Iraq's capital Baghdad in recent days, AFP journalists reported no drone or rocket attacks so far from late Wednesday onwards.
But on Thursday, two fighters from former paramilitary coalition Hashed al-Shaabi were killed in two separate strikes targeting their positions in northern Iraq, their group said.
Iraq has been drawn into the Middle East war triggered by the US-Israel attack on its neighbour Iran on February 28.
Strikes have targeted Iran-backed groups, which in turn have claimed near daily attacks on US interests in Iraq and across the region.
Kataeb Hezbollah said the group's secretary-general had "issued orders to suspend operations targeting the U.S. Embassy in Baghdad for a period of five days".
The Iran-backed group, designated by Washington as a "terrorist organisation", listed several conditions, including Israel ceasing its bombardment of the southern suburbs of Beirut.
That area is a bastion of Lebanon's Hezbollah, which is also Iran-backed and is at war with Israel.
Iraq's Kataeb Hezbollah also demanded "a commitment to refrain from bombing residential areas in Baghdad and other provinces".
Whenever "the enemy violates" the truce "the response will be immediate", it said, warning of more strikes after the five-day period.
The US embassy has been targeted by drone and rocket attacks several times in recent days, with air defences intercepting most of the projectiles.
A US diplomatic and logistics centre at Baghdad International Airport, which houses military personnel, has also been regularly targeted.
Only hours after the news of the ceasefire, two Hashed al-Shaabi fighters were killed in strikes in northern Iraq, according to the group, which said positions in the Nineveh region in Salah al-Din province were targeted.
The Popular Mobilisation Forces (PMF), part of Iraq's regular armed forces, blamed the strikes on the US and Israel.
Pro-Iran factions also have brigades that operate within the alliance, but have a reputation for acting on their own.
