US equity indexes were mixed in midday trading on Monday as crude oil futures rose amid reports of an updated peace proposal from Iran to end the war.

The Nasdaq Composite fell 0.8% to 26,018.3, with the S&P 500 down 0.4% to 7,380.6. The Dow Jones Industrial Average rose 0.1% to 49,559.1.

Iran has offered an updated proposal, which the White House sees as lacking meaningful improvement over the previous offer, rendering the latest version insufficient to reach a deal to end the war, a senior US official and a source briefed on the issue told Axios.

However, a senior Iranian source told Reuters that the US had agreed to release a quarter of Iran's frozen funds - totaling tens of billions of dollars - held in foreign banks. The Iranian source also told the news agency that Washington has shown more flexibility in allowing Iran to continue some peaceful nuclear activity under the supervision of the International Atomic Energy Agency.

President Donald Trump is expected to meet top national security advisers on Tuesday to discuss options for resuming military action, Axios reported. He said in a post on Truth Social at the weekend that "the Clock is Ticking" for Iran, adding that "they better get moving, FAST, or there won't be anything left of them. TIME IS OF THE ESSENCE!"

West Texas Intermediate crude oil futures climbed 2.1% to $107.64, and Brent crude futures advanced 2.1% to $111.55.