North Korea's Kim Jong Un and Vladimir Putin have discussed "possibilities" for military cooperation, in a highly scrutinised meeting for a suspected arms deal.

The pair met on Wednesday at the Vostochny space centre after Mr Kim arrived in his private armoured train.

Mr Putin also said he would help Pyongyang develop satellites.

The US says Moscow is buying weapons for its war on Ukraine, and warned any help would violate UN resolutions.

Mr Putin has also accepted an invitation from Mr Kim to visit North Korea. Few heads of state have visited the closed-off state.

Wednesday's meeting between the two sanctioned regimes, which included senior officials from both sides, took place at a time when their relations with the West are at an all-time low.

Mr Kim was warmly received by Mr Putin after travelling for two days to Russia's far east. Russian state media footage showed the two leaders grinning as they shook hands, before Mr Putin personally escorted Mr Kim around the space centre.

Citing historical ties between the Soviet Union and North Korea, Mr Putin welcomed his counterpart with the Russian proverb "an old friend is better than two new ones".

Asked if Russia would help North Korea build satellites, Mr Putin said "this is why we've come to Vostochny Cosmodrome", Russian media reported.

Mr Putin also said they would "discuss all topics" when asked if he would talk to Mr Kim about a weapons deal.

Meanwhile, Mr Kim appeared to express support for Mr Putin's war in Ukraine.

"Russia has risen to a sacred fight to protect its sovereignty and security against the hegemonic forces" of the West, Mr Kim told Mr Putin.

"We will always support the decisions of President Putin and the Russian leadership... and we will be together in the fight against imperialism."

The North Korean leader is expected to oversee a display of Russian warships later, as well as visit several factories and stop by the eastern city of Vladivostok on his way home. It is not known how long he will stay in Russia.