President Donald Trump said Saturday that negotiations with North Korean dictator Kim Jong Un could begin soon and that the leader issued a “small apology” for testing short-range missiles.

“In a letter to me sent by Kim Jong Un, he stated, very nicely, that he would like to meet and start negotiations as soon as the joint U.S./South Korea joint exercise are over. It was a long letter, much of it complaining about the ridiculous and expensive exercises,” Trump wrote Saturday on Twitter.

“It was also a small apology for testing the short range missiles, and that this testing would stop when the exercises end. I look forward to seeing Kim Jong Un in the not too distant future! A nuclear free North Korea will lead to one of the most successful countries in the world!” he continued.

The South Korean military said North Korea launched two short-range ballistic missiles into the sea Saturday, reported The Associated Press.

This comes after Kim said Wednesday that the country’s ballistic missile test Tuesday was a “warning” to South Korea and the U.S. during its joint drill. North Korea normally reacts strongly to annual exercises by the U.S. and South Korea.

Trump and Kim last met in June.