By Hyunsu Yim and Josh Smith

SEOUL (Reuters) -North Korean leader Kim Jong Un has left Pyongyang for Russia on his private train, state media reported on Tuesday, with photos showing that he is likely accompanied by top arms industry officials, among other diplomats and military commanders.

Kim left on Sunday in a trip that will include meetings with President Vladimir Putin, state news agency KCNA said.

American officials, who first reported that the visit was imminent, say the discussions are likely to include a possible deal for North Korea to provide Russia with weapons for the war in Ukraine.

Kim was accompanied by top government officials including military personnel, KCNA said.

Among the delegation are prominent military members of the ruling party, including Munitions Industry Department Director Jo Chun Ryong, and one analyst said the make-up of the delegation suggests the visit will mainly focus on defence industry cooperation and security affairs.

"The presence of Jo Chun Ryong indicates that North Korea and Russia will conclude some type of agreement for munitions purchases," said Michael Madden, a North Korea leadership expert at the Washington-based Stimson Center.

Photos released by state media showed military honour guards and crowds of people in dark suits and colourful dresses waving flowers and flags as he boarded the dark green train, which is believed to be armoured and carry other specialised equipment.

Kim's trip to Russia and meeting with Putin will be a full-scale visit, Kremlin spokesperson Dmitry Peskov said in a video posted online.

According to Peskov, the main topic of the talks will be relations between the neighbouring countries.

"We will continue to strengthen our friendship," he said.

Both Moscow and Pyongyang have denied earlier U.S. accusations that they had conducted arms deals, but the two countries have vowed to boost defence ties.

(Reporting by Hyunsu Yim; Writing by Josh Smith; Editing by Grant McCool and Stephen Coates)