SEOUL, March 20 (Reuters) - South Korea plans to hold its annual joint military drills with the United States on April 1 after delays during the Winter Olympics and Paralmypics, Seoul's defence ministry said on Tuesday.

Seoul said in January it had agreed with Washington to postpone the regular military exercises to ensure a peaceful Olympics, and the two Koreas held their first formal talks in more than two years ahead of the Games.

The South Korean and U.S. militaries usually begin the two programmes in March. The drills can involve as many as 17,000 U.S. troops and over 300,000 South Koreans.

This year's exercises will be held on a similar scale but without key U.S. strategic assets such as nuclear-powered aircraft carriers or bombers, Seoul officials said.

North Korea, which calls the drills a rehearsal for war, has threatened to take "counteraction" against the United States if it holds joint military exercises with South Korea.

But North Korean leader Kim Jong Un understood that the allies must continue their "routine" joint military exercises, South Korea's national security adviser said after meeting him earlier this month. (Reporting by Hyonhee Shin and Heekyong Yang Editing by Paul Tait)