SAMARRA: Iraq’s offensive to retake Tikrit from the Islamic State group was stalled Tuesday because of streets and buildings rigged with booby trap bombs and by the several hundred militants still holding out there.

Troops, police and militia fairly easily boxed the militants in over recent days, but mopping them up is proving to be far harder.

“The battle to retake Tikrit will be difficult because of the preparations (IS) made,” said Jawwad Al-Etlebawi, spokesman for Asaib Ahl Al-Haq, a Shiite militia playing a major role in the operation.

“They planted bombs on all the streets, buildings, bridges, everything... Our forces were stopped by these defensive preparations,” he told AFP.

“We need forces trained in urban warfare to break in,” he said, adding that the terrorists are surrounded and that “any besieged person fights fiercely.”

The assault on Tikrit, capital of Salaheddin province, began on March 2.

Loyalists had already failed three times retake the city, the hometown of Saddam Hussein, which was captured by IS last summer.

Meanwhile, IS posted pictures Tuesday of the beheading of four men it said were recruiters for the units.

The images show the men dressed in black kneeling in an empty street with knife-wielding militants standing behind them, after which they are pictured being beheaded.