The U.S. secretary of state begins a Mideast trip amid worries of broader conflict.

Secretary of State Antony J. Blinken was set on Friday to begin a diplomatic tour through the Middle East, as the Biden administration seeks to defuse tensions in the region, where fears are growing that the war in Gaza could spiral into a broader conflict.

Skirmishes along Israel’s border with Lebanon and attacks in the Red Sea by the Houthi militia group in Yemen have kept anxiety high throughout the three months of war. But this week, the assassination of a Hamas leader in Lebanon and twin blasts in Iran that killed at least 84 appeared to deepen worries of a regionwide clash that could draw in the United States.

In his weeklong trip, Mr. Blinken is expected to make nine stops, including in Israel, the West Bank and Egypt. It is his fourth visit to the region since the Hamas-led attack on Oct. 7 sparked Israel’s war in the Gaza Strip.

Matthew Miller, a spokesman for the State Department, said it was “in no one’s interest” for the conflict to spread beyond Gaza and that it was a priority for Mr. Blinken to get allies and others in the region to use their influence to deter any escalation.

“The risk is real; the concern is high,” he told reporters at a regularly scheduled briefing on Thursday.

The assassination on Tuesday of a top Hamas leader in a suburb of Beirut — a killing that Hamas, Lebanon and U.S. officials said Israel was behind — prompted the Lebanese militant group Hezbollah to pledge a response.

A day later, Iranian officials initially appeared to blame Israel for the deadly explosions in Kerman, Iran, at a memorial for Iran’s former top general, Qassim Suleimani. On Thursday, though, the Islamic State extremist group claimed responsibility for the attack on its Telegram page.

U.S. officials, along with a dozen other nations, issued a warning this week directed at the Iran-backed Houthis, who have been engaging in near-daily missile, drone and seaborne attacks on commercial vessels traveling through the Red Sea.

On his trip, Mr. Blinken will also discuss the need for increased humanitarian aid for Gaza’s civilians and efforts to secure the release of remaining hostages, including American citizens, Mr. Miller said.