Talks between the United States and Iran stumbled again over the weekend. Replying to an American proposal to reopen the strait and negotiate and end to the war, Iran called for U.S. war reparations, recognition of its sovereignty over the Strait of Hormuz and an end to American sanctions, Iran’s state-owned broadcaster reported on Monday.

The Iranian offer is a “piece of garbage,” Mr. Trump told reporters in the Oval Office, adding that Tehran was in the grip of “lunatics.” On Sunday, before any elements of the counterproposal were made public, Mr. Trump dismissed it as “TOTALLY UNACCEPTABLE,” but did not specify his objections.

Iran’s demands for reparations and sovereignty over the strait would almost certainly be non-starters for the United States, while ending sanctions would be possible only if Iran were willing to make major concessions on its nuclear program.

A week of strikes in the Persian Gulf had already rattled their month-old cease-fire. The truce was intended to provide an opening to negotiate a more comprehensive peace deal and end Iran’s de facto blockade of the strait, a vital waterway for oil and gas shipments.

Small-scale attacks have continued around the strait. On Sunday, the United Arab Emirates said it had again been attacked by Iranian drones, and last week American warships fired on military facilities along Iran’s coast.

Here’s what else we’re covering:

• Oil prices: Oil prices rose and stocks opened relatively flat for trading in the United States on Monday as investors reacted to Mr. Trump’s swift rejection of Iran’s response. Oil companies have posted huge profits despite the shipping disruptions; Aramco, Saudi Arabia’s national oil company, said on Monday that its first-quarter profits had jumped by 25 percent.

• Enriched uranium: In an interview with the syndicated news show “Full Measure” aired on Sunday, Mr. Trump said that the U.S. was surveilling Iran’s remaining enriched uranium stockpile and would “get that at some point.” The president’s comments on the stockpiles have been inconsistent; last month, he said he didn’t care about the uranium because it was buried “so far underground.”

• China summit: Mr. Trump hoped to have the conflict resolved by the time he headed to China this week to meet with Mr. Xi, who is eager to see an end to the fighting in Iran.