The Iraqi government has received a delivery of Russian-made fighter planes it hopes will turn the tide against Sunni rebels who have seized large parts of the country.

Iraqi security officials confirmed five Sukhoi-25 jets, which were purchased second-hand from Russia, had arrived in Baghdad on Saturday.

Pictures released by the defence ministry showed the jets taxiing on a runway towards a hangar.

Military officials are banking on the aircraft bolstering efforts by the army to retake territory seized by Sunni rebels led by the Islamic State in Iraq and the Levant earlier this month.

Al Jazeera's Imran Khan, reporting from Baghdad, said the move to buy jets from Russia was a snub to the US, which had promised 34 F-16 fighters to the Iraqis. Khan said the government was frustrated by delays with their delivery.

Iraqi Air Force officials said the jets would be ready to use in sorties within three to four days, but the Iraqis require technical help and parts to make them operational.

"The Iraqis have Hellfire missiles that are not compatible with these new Russian Sukhoi jets," Khan said.

Meanwhile, the formation of a new government faced obstacles as the biggest bloc in the parliament chose to abstain from an upcoming parliamentary session on July 1.

On Sunday, Iraq's National Coalition led by former Prime Minister Iyad Allawi announced that it demanded the creation of a "road map to stop the security deterioration and heal country's rift".

Politicians from the 21-seat bloc said in a statement that more time was needed to avoid the mistakes of the last government.