Oil prices jumped to their highest since late 2018 on news the United States is likely to ask all importers of Iranian oil to end their purchases or face U.S. sanctions.  A source confirmed to Reuters a report by the Washington Post that the administration will terminate the sanctions waivers it granted to some importers of Iranian oil late last year.

In November, the U.S. reimposed sanctions on exports of Iranian oil after President Donald Trump unilaterally pulled out of a 2015 nuclear accord between Iran and six world powers.

China, India, Japan, South Korea and Taiwan were among the eight main buyers of Iranian oil that were granted waivers to the sanctions that allowed them limited purchases for six months.

The Indian rupee weakened 0.5 percent to 69.73 against dollar, touching its weakest point since March 11, while the Philippine peso traded 0.7 percent lower.

The Thai baht eased 0.2 percent, after data showed the country's customs-cleared exports fell 4.88 percent in March, after unexpectedly increasing in February, due to falling shipments of electronics - a key driver of Thai growth.

Thailand's central bank governor said that economic growth for the year should be on track if the next government can be formed by June.

The outcome of Thailand's first elections since a 2014 coup remains uncertain, and might not be known until after official results are due on May 9.

The Taiwan dollar was largely flat, ahead of export orders data for March.

A Reuters poll showed that Taiwan's export orders likely declined for a fifth month in March, as a prolonged downturn in global tech demand has hurt manufacturers in the trade-reliant economy.

SOUTH KOREAN WON PRESSURED

Dismal trade data and fears of tension in the Korean peninsula weighed on the won on Monday, pulling it down 0.5 percent to 1,142.70 against the dollar.

Trade data released earlier in the session showed the country's exports for the first 20 days of April shrank 8.7 percent from a year earlier.

"The South Korean won could see more selling on increased geopolitical risks, as North Korea rejects further negotiations with U.S. Secretary of State (Mike) Pompeo, and even conducted a new tactical guided weapon test," Mizuho Bank said in a note.

Pompeo said on Friday that diplomatic efforts will continue toward the goal of denuclearization of North Korea, a day after a North Korean official said it no longer wanted to deal with him in talks.