The U.S. has been pressing Israel for months to allow more aid into Gaza. Mr. Blinken reinforced that message with a visit to a warehouse with boxes of canned food that were intended to be brought to Gaza on trucks organized by the United Nations World Food Program.

Sheri Ritsema-Anderson, the resident U.N. coordinator in Jordan, told reporters that in her 15 years working in the Middle East, she had never seen a humanitarian situation as dire as the one in Gaza, describing it as an “epic catastrophe.”

She said about 220 trucks of various types of aid and fuel are now getting into Gaza daily, but that is only a fraction of the amount needed.

Before the Oct. 7 Hamas attacks that prompted Israel to launch airstrikes and a ground invasion in Gaza, which has forced most of the territory’s 2.2 million Palestinians from their homes, about 600 to 800 trucks carried supplies into Gaza each day. The territory has been under a de facto blockade by Israel, with the assistance of Egypt, for more than 16 years.

Mr. Blinken praised the U.N. food program, saying it was doing its work “at tremendous risk” — a reference to the dangers posed by Israeli airstrikes. And he emphasized the need to effectively distribute the aid “everywhere in Gaza.” Aid trucks are entering Gaza through border crossings in the south, after being inspected by Israeli authorities. Although Israel has been withdrawing some combat forces from northern Gaza, much of the aid is not reaching the north, the most devastated part of the strip.

In his meeting with the king, Mr. Blinken also reiterated that the U.S. was against moving Palestinians out of Gaza, according to Mr. Miller. Two far-right Israeli ministers endorsed that idea last week, drawing harsh rebukes from the U.S. and other countries.

Mr. Blinken flew into Doha, Qatar, in the afternoon and met with the emir, Sheikh Tamim bin Hamad al-Thani, and with the prime minister, Sheikh Mohammed bin Abdulrahman bin Jassim al-Thani, who also acts as the foreign minister. The officials spoke about possibilities for trying to get Hamas to release more hostages and for ensuring the conflict does not spread across the region.

“This is a moment of profound tension in the region,” Mr. Blinken said at a news conference with the prime minister. “This is a conflict that could easily metastasize.”

Mr. Blinken pointed to the recent attacks in the Red Sea by the Houthi militia of Yemen, which have jeopardized global shipping. Dealing with the threat from the Houthis was one of the topics discussed by American and Qatari officials in Doha. Tim Lenderking, the U.S. special envoy for Yemen, joined Mr. Blinken’s delegation in Doha for the talks.

Mr. Blinken also expressed sadness at the killing on Sunday in Gaza of Hamza Dahdouh, a freelance journalist who was the eldest son of Wael Dahdouh, the bureau chief for Al Jazeera in Gaza.

Sheikh al-Thani said that Qatar was trying to push forward with hostage talks, despite the potential for the recent fatal bomb attack in Lebanon against Saleh al-Arouri, the deputy political leader of Hamas, to set back discussions. The bombing has been attributed to Israel.

“It has been ongoing,” the sheikh said of the hostage talks, adding that there have been “challenges, ups and downs, throughout the process.”

After his meetings in Doha, Mr. Blinken flew to Abu Dhabi to have meetings with officials in the United Arab Emirates on Monday.

Mr. Blinken was in Turkey on Saturday, meeting with his Turkish counterpart and with President Recep Tayyip Erdogan, with whom he discussed the need to keep the Gaza conflict from spreading, among other subjects, according to a State Department statement. Later, he met with Greece’s prime minister, Kyriakos Mitsotakis, on the island of Crete.

Speaking to reporters, Mr. Blinken indicated that Turkey could play a role in a plan for postwar Gaza.

“I think from our conversations today, it’s clear that Turkey is prepared to play a positive, productive role in work that needs to happen the day after the conflict ends,” he said.