BAGHDAD: Iraqi forces thrust into the city of Fallujah from three directions on Monday marking a new and perilous urban phase in the week-old operation to retake the jihadist bastion. Led by the elite counter-terrorism service (CTS), Iraq’s best trained and most seasoned fighting unit, the forces pushed in before dawn, commanders said. “Iraqi forces entered Fallujah under air cover from the international coalition, the Iraqi air force and army aviation, and supported by artillery and tanks,” said Lieutenant General Abdelwahab al-Saadi, the commander of the operation. “CTS forces, the Anbar (provincial) police and the Iraqi army, at around 4:00 am (0100 GMT), started moving into Fallujah from three directions,” he said. “There is resistance from Daesh,” he added, using an Arabic acronym for IS. CTS spokesman Sabah al-Noman told AFP: “We started early this morning our operations to break into Fallujah.” The involvement of the elite CTS marks the start of a phase of urban combat in a city where in 2004 US forces fought some of their toughest battles since the Vietnam War. The week-old operation had previously focused on retaking villages and rural areas around Fallujah, which lies just 50 kilometres (30 miles) west of Baghdad. Only a few hundred families have managed to slip out of the Fallujah area ahead of the assault on the city, with an estimated 50,000 civilians still trapped inside, sparking fears the militants could try to use them as human shields. The only families who were able to flee so far lived in outlying areas, with the biggest wave of displaced reaching camps on Saturday night. “Our resources in the camps are now very strained and with many more expected to flee we might not be able to provide enough drinking water for everyone,” said Nasr Muflahi, the Norwegian Refugee Council’s Iraq director. “We expect bigger waves of displacement the fiercer the fighting gets.”