BAGHDAD, Iraq (CNN) -

After much anticipation over how it would address the country's turmoil, Iraq's new parliament postponed its first session until next week, citing a lack of a quorum.

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

"We are going to postpone because of an urgent matter," the speaker of the parliament said. He did not say what the urgent matter was, and it was not immediately clear what happened.

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 expected Prime Minister Nuri al-Maliki to call for the formation of a new government Tuesday as Iraq battles militants from the Islamic State in Iraq and Syria.

Al-Maliki and his Shiite-dominated government have been under pressure by Western and Arab diplomats to be more inclusive of Iraq's Sunni minority, who say they have been marginalized and cut out of the political process by the government.

Under Iraq's constitution, the parliament has 75 days from when it convenes to pick a prime minister.

Lawmakers are under pressure to move faster, but the political body has had trouble moving swiftly in the past. The last time parliament met to pick a prime minister, it took nearly 10 months.

American and Arab diplomats have told CNN that the United States probably won't launch military strikes against ISIS and its allied fighters before a new government is formed in Iraq.

U.S. sends more troops to Iraq

But the United States is increasing its military presence in Iraq, ordering 300 more troops to the besieged country, the Pentagon announced Monday.

ISIS militants have "continued to pose a legitimate threat to Baghdad and its environs," a U.S. official told CNN. "We have seen them reinforce themselves around Baghdad enough to convince us more troops was the prudent thing to do."

The new troops, 200 of whom arrived Sunday and Monday, will provide security for the U.S. Embassy, the Baghdad airport and other facilities in Iraq, Pentagon spokesman Rear Adm. John Kirby said.

Helicopters and drones are among the equipment included in the deployment, Kirby said in a statement.

The 300 troops are in addition to 300 U.S. advisers who will help train Iraq's security forces. They will bring the total of American forces in Iraq to about 800 troops.

Staggering death tolls

The magnitude of the Iraq crisis can be illustrated in the sharp rise in deaths over the past two months.

At least 2,417 Iraqis died in violence in June, according to the United Nations Assistance Mission for Iraq.

Of those, 1,531 were civilians, including 270 civilian police officers, and 886 were members of the Iraqi security forces, UNAMI said.

In May, 994 people died, according to the United Nations.