MICHAEL GORDON

Russia has asked the Obama administration for permission to fly surveillance planes equipped with high-powered digital cameras over the United States, fueling a long-simmering debate among Pentagon and intelligence officials over the Open Skies Treaty.

Kurdish forces aided by thousands of lightly armed Yazidi fighters captured a strategic highway on Thursday in northern Iraq in the early stages of an offensive to reclaim the town of Sinjar from the Islamic State, which seized it last year and murdered, raped and enslaved thousands of Yazidis.

As the United States prepares to intensify airstrikes against the Islamic State in Syria, the Arab allies who with great fanfare sent warplanes on the initial missions there a year ago have largely vanished from the campaign.

The raid was the first time U.S. soldiers had been confirmed to be directly accompanying local forces in Iraq onto the battlefield against the Islamic State since President Barack Obama sent troops back to the country last year.

Secretary of State John Kerry announced that the Obama administration had agreed to negotiate with the Kremlin on the crisis.

In a major shift of focus in the battle against the Islamic State, the Obama administration is planning to establish a new military base in Anbar province and send 400 U.S. military trainers to help Iraqi forces retake the city of Ramadi.

Iran and the world powers said here Thursday that they had reached a surprisingly specific and comprehensive general understanding about the next steps in limiting Tehran’s nuclear program, though Western officials said many details needed to be resolved before a final agreement in June.

If U.S. negotiators are ultimately able to conclude a “political understanding” with Iran on its nuclear program, as they said they were striving to do Thursday morning, the seeds might have been planted earlier in the week.

The one-day extension came with a White House warning that the Obama administration was prepared to step back from its diplomatic efforts if it concluded that the initial accord could not be reached.

With a negotiating deadline just two days away, Iranian officials on Sunday backed away from a critical element of a proposed nuclear agreement, saying they are no longer willing to ship their atomic fuel out of the country.

The U.S. government has concluded that the passenger jet felled over Ukraine was shot down by a Russian-made surface-to-air missile launched from rebel-held territory and most likely provided by Russia to pro-Moscow separatists, officials said Friday.

North Carolina’s new restrictions on voting may favor the Republican Party, but Democrats must prove more than that to beat them in court. GOP legislators who passed the rules last summer say they are designed to streamline and modernize the state’s voting while also blocking election fraud, a problem they describe as rampant and undetected.