A South Korean newspaper reported Saturday that the United States has detected signs of North Korea making preparations for a missile launch — news that comes amid rumors of leader Kim Jong Un’s ill health.

According to the electronic version of the Dong-A Ilbo newspaper, a mobile launch vehicle was on Friday deployed in an airfield in Sondok, in South Hamgyong province. U.S. officials believe a launch could occur within 48 hours.

The possibility of North Korea testing a missile with a longer range than a short-range missile has been raised, the report said.

North Korea on April 14 fired several projectiles, believed to be short-range cruise missiles, into the Sea of Japan.

In March, the country test-fired short-range missiles on four occasions.