A member of the Iraqi forces advances through the streets of the Old City of Mosul on June 25, 2017.

:: Iraqi forces on Monday were searching neighborhoods of west Mosul they retook weeks ago after a surprise militant attack on their rear that left several dead, officials said.

The attack, which was claimed by ISIS, sowed panic among residents who returned to live in the Tanak and Yarmuk neighborhoods of west Mosul.

A top commander in the Counter-Terrorism Service (CTS), which sent forces to fight the ISIS gunmen, said the attackers had infiltrated the area by blending in with returning displaced civilians.

“The group came with the displaced and settled in the Tanak district. They regrouped and launched counter-attacks,” Staff Lieutenant General Abdulwahab al-Saadi told AFP.

“Yarmuk is being searched house to house,” he said, adding that two groups of ISIS attackers were still believed to be in the area, which lies on the western edge of the city.

A CTS medic said the attack had caused several victims but he could not say how many.

“There are martyrs who were killed by Daesh,” the medic said, using an Arabic acronym for ISIS.

He said 15 to 20 militant fighters were also killed in the battle.

Iraqi forces, led by the CTS, have for a week been pressing a perilous assault into the Old City in central Mosul, the last pocket still controlled by the militants.

While the exact circumstances were unclear, Sunday night’s attack was described as a diversionary tactic by west Mosul “sleeper cells” to ease the pressure on the Old City, where the militants appear to be on their last legs.

“The sleeper cells carried out a surprise attack against the security forces, in an attempt to ease the siege on the Old City,” a local official told AFP on condition of anonymity.

“Operations to flush out pockets controlled by Daesh are ongoing,” he said.