BAGHDAD: Iraqi forces battling the Islamic State group focused their offensive on Sunday on the city of Ramadi, backed by Sunni tribal fighters that the US plans to arm.

Authorities in the city implemented a 24-hour curfew as Iraqi armed forces and tribesmen fought to regain Ramadi's eastern Sijariya neighborhood, which the extremist group said it captured on Friday.

Iraqi Prime Minister Haider al-Abadi has ordered more aerial support and weapons for both soldiers and Sunni militiamen battling the Islamic State group in Anbar province, where Ramadi is the provincial capital.

The US and Iraqi governments have been working to woo Sunni tribesmen to support the fight, proposing the establishment of a national guard program that will include arming and paying loyal tribesmen.

The Pentagon plans to buy a range of arms for Iraq's tribesmen, including 5,000 AK-47s, 50 rocket-propelled grenade launchers, 12,000 grenades and 50 82 mm mortars. The arms supply, described in a document that will be sent to Congress of its approval, said the estimated cost to equip an initial Anbar-based force of tribal fighters is USD 18.5 million, part of a USD 1.6 billion request to Congress that includes arming and training Iraqi and Kurdish forces.

"Failure to equip these forces mean a less effective armed opposition to counter the Islamic State and its ability to gain the local support necessary to effectively control the areas it holds," the document said.

Already, the Islamic State group fighters has lined up and shot several men from the al-Bu Fahd tribe, which is taking part in the fight against them. They also have killed more than 200 men, women and children from Anbar's Sunni Al Bu Nimr tribe in recent weeks, apparently in revenge for the tribe's siding with Iraqi security forces and, in the past, with US forces.

Meanwhile, Iraq's Supreme Judicial Council sentenced a former Sunni lawmaker to death for killing two Iraqi soldiers in 2013. The arrest of Ahmed al-Alwani last year stirred sectarian tensions as he had become a symbol for Sunni protests against Iraq's Shiite-led government. Al-Alwani can appeal the verdict.