BAGHDAD — Confronting the threat of civil war in Iraq, U.S. Secretary of State John Kerry flew to Baghdad today to personally urge the Shiite-led government to give more power to political opponents before a Sunni insurgency seizes more control across the country and sweeps away hopes for lasting peace.

The meeting scheduled between Kerry and Iraqi Prime Minister Nouri al-Maliki was not expected to be friendly, given that officials in Washington have floated suggestions that the Iraqi premier should resign as a necessary first step toward quelling the vicious uprising. As al-Maliki has shown no sign of leaving.

Still, having suffered together through more than eight years of war — which killed nearly 4,500 American troops and more than 100,000 Iraqis — the two wary allies are unwilling to turn away from the very real prospect of the Mideast nation falling into a fresh bout of sectarian strife.

“This is a critical moment where, together, we must urge Iraq’s leaders to rise above sectarian motivations and form a government that is united in its determination to meet the needs and speak to the demands of all of their people,” Kerry said a day earlier in Cairo. He was there in part to meet with Egyptian President Abdel-Fattah el-Sissi to and discuss a regional solution to end the bloodshed by the insurgent Islamic State of Iraq and the Levant, or ISIL.

Since the start of this year, and peaking this month, ISIL has overtaken several cities in Iraq’s west and north, and over the past weekend was controlling several main border crossings between Iraq and Syria.

A senior State Department official said the insurgents’ recent march on Baghdad has been slowed, although concerns remain that ISIL will attack the golden-domed Shiite shrine to the Imam al-Askari in Samarra. That city, in Sunni territory in north-central Iraq, was the site of a 2006 bombing that triggered the worst of the war’s sectarian fighting. Last week, Senate Majority Leader Harry Reid declared that Iraq is currently in a civil war.