North Korean leader Kim Jong-un is seeking to visit Russia in an apparent move to boast his close ties with the neighboring country after the breakdown of his summit with U.S. President Donald Trump, a former U.S. intelligence official was quoted as saying, Yonhap reports.

Andrew Kim, who retired last year as head of the Central Intelligence Agency’s Korea Mission Center, made the remark during a closed-door lecture in Seoul, according to local daily Donga Ilbo.

The former CIA official arrived in South Korea on Monday, the report said.

Speculation has arisen that the North’s Kim could pay his first trip to Russia following the breakdown of his second summit with Trump in Hanoi last month.

Pyongyang has been stepping up its diplomacy with Moscow, with three senior North Korean officials making back-to-back visits to Russia this month.