South Korean stocks hit fresh record, building on historic monthly rally in April

South Korean stocks rose Monday to hit a fresh record, following their strongest monthly gain in April, as investors weighed tensions between Iran and the U.S. and a U.S. plan to reopen shipping in the Strait of Hormuz.

The U.S. would attempt to "free" stranded ships affected by the Strait of Hormuz closure since the start of the Iran war, U.S. President Trump said in his Truth Social post Sunday.

Dubbed "Project Freedom," the effort is set to begin on Monday, Middle East time and will focus mainly on getting civilian ships flagged in countries not affiliated with the conflict out of the contested waterway so they can "freely and ably get on with their business."

"U.S. military support to Project Freedom will include guided-missile destroyers, over 100 land and sea-based aircraft, multi-domain unmanned platforms, and 15,000 service members," the U.S. Central Command said shortly after Trump's announcement.

Oil prices fell following the announcement of "Project Freedom". West Texas Intermediate futures for July delivery fell 0.59% to $101.34 per barrel as of 7:38 p.m. ET. Brent crude futures were 0.27% lower at $107.88 per barrel.

Hong Kong's Hang Seng index futures were at 25,992, compared with the index's last close of 25,776.53.

Australia's S&P/ASX 200 was marginally lower. Markets in Japan and China are closed for a public holiday.

U.S. stock futures traded close to the flatline Sunday night. S&P 500 futures added 0.1% and Nasdaq 100 futures gained 0.1%. Futures tied to the Dow Jones Industrial Average added 100 points, or 0.2%.

On Friday, both the S&P 500 and Nasdaq Composite rose to new all-time intraday and closing highs. The broad market index rose 0.29%, while the tech-heavy Nasdaq climbed 0.89%. The Dow bucked the trend, however, slipping 152.87 points, or 0.31%.

— CNBC's Lisa Kailai Han and Garrett Downs contributed to this report.