BAGHDAD/ SAMARRA - Iraq's huge offensive to retake Tikrit from the Islamic State group was stalled on Tuesday by a slew of bombs and the several hundred jihadists holding out in the city.

While Iraqi troops and militia were able to surround the jihadists in Tikrit with relative ease, ousting them from the city's streets has proved far harder.

‘The battle to retake Tikrit will be difficult because of the preparations (IS) made,’ said Jawwad al-Etlebawi, spokesman for the Asaib Ahl al-Haq, a Shiite militia that is playing a major role in the operation alongside the regular army. ‘They planted bombs on all the streets, buildings, bridges, everything. For this reason, our forces were stopped by these defensive preparations,’ Etlebawi told AFP. ‘We need forces trained in urban warfare to break in,’ he said, adding that the jihadists are surrounded, ‘but any besieged person fights fiercely.’

The operation to recapture Tikrit, the capital of Salaheddin province, began on March 2. Iraqi forces have tried and failed three times before to retake the city, which was the hometown of executed dictator Saddam Hussein. Interior Minister Mohammed Ghabban said on Monday that the latest operation had been halted to avoid casualties and protect infrastructure.

But it is unclear how stopping operations against the jihadists for anything other than an extended siege would change either of those situations, unless Iraqi forces receive additional external support such as air strikes. Staff Lieutenant General Abdulwahab al-Saadi, the head of the military command responsible for Salaheddin, told AFP on Sunday that Iraqi forces in Tikrit needed air support from the US-led coalition.

Saadi said that he asked the defence ministry to make the request to the coalition, but that no air support had yet been forthcoming.

Iraq has formed paramilitary units dubbed the Popular Mobilisation force to fight alongside the regular army. It is made up largely of Shiite militiamen but the government has attempted to recruit Sunni Arab volunteers to it to join the battle in overwhelmingly Sunni Arab Tikrit.

IS posted pictures on Tuesday of the beheadings of four men it said what were recruiters for the units in Salaheddin province. 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. IS has carried out numerous atrocities in areas it controls, including public beheadings and mass executions as well as enslavement and rape, and caused millions to be displaced.

IS spearheaded a sweeping offensive that overran large areas north and west of Baghdad last June. It also holds significant territory in neighbouring Syria, where it has taken advantage of the uprising against President Bashar al-Assad, now in its fifth year, to oust government forces and rival rebel groups from a swathe of the east and north.

Moreover, the Islamic State group posted pictures Tuesday of the beheadings of four men it said were recruiters for pro-government militia fighting its militants in northern Iraq. The images show four men dressed in black kneeling in an empty street with knife-wielding militants standing behind them, after which they are pictured being beheaded. Text accompanying the photographs said the beheadings were carried out in Salaheddin province, where Iraqi troops backed by militia are fighting to retake the provincial capital Tikrit from IS. The exact location where the photos were taken was unclear, and their authenticity could not be independently confirmed. IS spearheaded a sweeping offensive that overran large areas north and west of Baghdad last year. It has carried out numerous atrocities in areas it controls ranging from public beheadings to enslavement and rape.

In the meanwhile, the Philippines said Tuesday a media report that the Islamic State group had abducted four Filipino medical workers in the Libyan city of Sirte was wrong. One report cited members of a rival militia saying four nurses from the Philippines were abducted from Ibn Sina hospital on Monday.

, while another said about 20 medical workers, including Filipinos, were abducted at the same hospital.

‘The report about four Filipino nurses being abducted in Sirte are false,’ foreign department spokesman Charles Jose told reporters. Jose said the Philippine embassy in Libya has been in touch with one of the four Filipino nurses, who informed the mission they had been safely evacuated from Sirte. ‘The four Filipinos were not actually kidnapped. They were actually taken from their accommodations to a safer place,’ he said.

The four were moved elsewhere by a ‘local friend’, he said, declining to comment on reports that a militia group battling the Islamic State group had escorted several medical workers out of Sirte. Jose, meanwhile, said there was still no news on the whereabouts or condition of seven other Filipinos abducted in Libya this year. Four Filipino workers were among nine foreigners abducted from the southern Libyan oilfield of Al-Ghani this month, while three Filipino workers were seized in the Al-Mabruk oilfield in early February.

‘No one has claimed responsibility for the abductions, so we do not really know who to negotiate with. There are many armed groups in Libya but we do not know which one to speak to,’ he said. Jose said the Philippines has evacuated more than 4,200 Filipinos from Libya since July last year. However about 4,000 others have remained, lured by high salaries. Jose said 30 medical workers remained in Sirte. Filipino medical workers make up the backbone of Libya's hospital staff and are being offered financial incentives to stay, the Philippine government said earlier. Libya has been wracked by conflict for the past four years, with rival governments and powerful militias now battling for control of key cities and the country's oil riches.