SEOUL (Reuters) - North Korea threatened on Wednesday to retaliate if the United States goes ahead with scheduled military drills with South Korea, ramping up pressure on Washington to change course as a year-end North Korean deadline for U.S. flexibility approaches.

FILE PHOTO - A North Korean flag flies on a mast at the Permanent Mission of North Korea in Geneva October 2, 2014. REUTERS/Denis Balibouse/File Picture

The statement came even though Washington said last week that the joint aerial exercise planned for next month would be reduced in scope from previous drills.

“It is self-defense rights” to retaliate against any move which threatens its sovereignty and security, according to a statement from the State Affairs Commission, without elaborating.

It is rare for the commission, the supreme governing body chaired by North Korean leader Kim Jong Un, to release a statement.

Last week, a senior North Korean diplomat also blamed the U.S. joint aerial drill for “throwing cold water” over talks with Washington. Pyongyang opposes U.S.-South Korean joint military exercises, viewing them as a rehearsal for invasion.

In its latest statement, Pyongyang said it had taken measures to calm Washington’s concerns but that the United States had failed to reciprocate, leaving it with a “feeling of betrayal.”

Asked to comment on the North Korea statement, the U.S. State Department made no reference to the military exercises, but a spokeswoman referred to an agreement reached between Kim Jong Un and President Donald Trump at their first summit in Singapore in June 2018.

“President Trump remains committed to making progress toward the Singapore commitments of transformed relations, building lasting peace, and complete denuclearization,” she said.

Immediately following his first meeting with Kim, Trump made a surprise announcement that the United States would suspend military drills with South Korea. Since then, major exercises have been halted or scaled back.

Kim in April gave the United States a year-end deadline to show more flexibility in stalled denuclearization talks.

This statement followed the collapse of his second summit with Trump in Hanoi in February, and has raised concerns that North Korea could return to nuclear bomb and long-range missile testing suspended since 2017.

North Korea has tested the limits of engagement with a string of short-range missile launches, and analysts say it appears to have been emboldened to toughen its approach by the impeachment inquiry into Trump in Washington.

Senior Democratic and Republican lawmakers presented dueling narratives on Wednesday as the congressional impeachment inquiry threatening Trump’s presidency entered a crucial new phase with the first televised public hearing.