BAGHDAD, Iraq (CNN) -

A defiant Nuri al-Maliki announced Friday that he would not withdraw his name as a candidate for prime minister, a statement that came hours after a leading lawmaker alleged he had agreed not to put his name forward to make it easier to pick a new leader

"I will never back down nominating myself as prime minister," he said, according to the statement read on state-run Iraqiya TV. "No one has the right to place any conditions."

Earlier in the day, a spokesman for al-Maliki denied a claim by Parliament's caretaker speaker, Osama al-Nujaifi, that the Prime Minister had agreed not to seek another term in exchange for concessions from Nujaifi.

"Mr. al-Maliki has now realized that there is no way to be nominated for the position of prime minister. So he agreed ... not to be nominated for the same post on condition of the withdrawal of my nomination for Parliament speaker," Nujaifi said in a video statement posted on his Facebook page.

Al-Maliki and his Shiite-dominated government have been under enormous international pressure to be more inclusive of the country's minority Sunni population, who say they have been marginalized and cut out of the political process.

Under the Iraqi constitution, al-Maliki and Nujaifi are in caretaker roles until Parliament can appoint people to the new positions.

Al-Maliki's State of Law political party gained a majority of the seats in Parliament during the April elections, but not enough for a supermajority.

"I need to speak to you in a transparent way because of the conspiracy facing Iraq," al-Maliki said in the statement.

"The State of Law coalition has been fighting a fierce battle, and it has faced many accusations backed by foreign interests. Despite the black accusations I have faced personally, we still have managed to a clear victory in an election that has been widely recognized by the international community as legitimate."

The statement comes after Iraq's new parliament postponed its first session this week, citing a lack of quorum.

The move came after 90 members of Parliament failed to return after a 30-minute morning break during the scheduled session Tuesday.

The newly elected parliament convened with 255 out of 328 elected officials attending, which was enough for a legal quorum, the speaker said. But when many failed to return after the break, there were not enough members to continue.

Many had expected al-Maliki to call for the formation of a new government as Iraq battles extremists with the Islamic State in Iraq and Syria, a militant group now referring to itself as "Islamic State."

Top Shiite cleric: Lack of accord 'a regrettable failure'

During Friday prayers, a representative of Ayatollah Ali al-Sistani said the lack of agreement to form a new government "was a regrettable failure."

"With the sensitive circumstances that Iraq is living under, all parties especially political leadership should avoid hardliner political speech that lead to more crises and respect the constitution and its articles," Ahmed al-Safi said during the sermon in the holy city of Karbala.

He called on lawmakers to speed up efforts to form a new government. Parliament is scheduled to resume next week.

Suicide bombing kills 15 at Samarra security checkpoint

A suicide car bomb exploded at a security checkpoint near Samarra on Friday, killing at least 16 people and injuring 15 others, police said.

Most of the killed and wounded were Iraqi soldiers and police officers, the officials said.