UPDATE 4-Assault on Islamic State enclave is as good as over-SDF

Islamic State was close to defeat in its final enclave on Tuesday after ferocious bombardments overnight and the U.S.-backed Syrian Democratic Forces (SDF) said the offensive to capture the area was nearly over. The beseiged enclave of Baghouz is the last shred of territory held by the jihadists who have been driven from roughly one third of Iraq and Syria over the past four years by its enemies, including a U.S.-led international coalition.

"The operation is over, or as good as over, but requires a little more time to be completed practically on the ground," SDF spokesman Kino Gabriel told al-Hadath TV. Islamic State was still putting up resistance with weapons including car bombs. The Baghouz enclave was targeted with barrages of rockets overnight and fires raged inside, but the bombardments ceased on Tuesday morning.

The SDF has been laying siege to Baghouz for weeks but repeatedly postponed its final assault to allow the evacuation of thousands of civilians, many of them wives and children of Islamic State fighters. It finally resumed the attack on Sunday, backed by coalition air strikes. Gabriel said 25 Islamic State fighters had been confirmed killed so far in clashes, in addition to an unknown number of militants killed by air strikes. Another SDF official earlier said 38 jihadists had been confirmed killed.

The SDF, which is spearheaded by the Kurdish YPG militia, has been advancing slowly into Baghouz to minimise its losses from sniper fire and landmines. Three SDF fighters have been killed, Mustafa Bali, head of the SDF media office, said on Twitter.

Islamic State's defences include extensive tunnels and Islamic State's most hardened foreign fighters are holed up inside the enclave, the SDF has said. However the United States does not believe any senior Islamic State leaders are in Baghouz, assessing they have gone elsewhere as part of the group's shift towards guerrilla tactics, a U.S. defence official has said.

The group still operates in remote territory elsewhere and it is widely assessed that it will continue to represent a potent security threat. The bulk of the people evacuated from the diminishing Islamic State territory have been transported to a camp for internally displaced people in al-Hol, in northeastern Syria, where the United Nations says conditions are dire.

The camp, designed to accommodate 20,000 people, is now sheltering more than 66,000, the U.N. said. The World Health Organisation on Tuesday said 106 people, mainly infants, have died on the journey to al-Hol, which takes at least six hours, since December.

Obdurate support voiced by many evacuees for Islamic State, particularly among foreigners, has posed a complex security, legal and moral challenge. Those issues were underscored on Friday with the death of the newborn son of Shamima Begum, a British woman who left to join Islamic State when she was a schoolgirl.

(Additional reporting by Tom Miles in Geneva, Lisa Barrington and Tom Perry in Beirut and Stephanie Nebehay in Geneva; Writing by Tom Perry; editing by John Stonestreet and Angus MacSwan)