SEOUL, South Korea (AP) Russian President Vladimir Putin and North Korean leader Kim Jong Un signed a new partnership that includes a vow of mutual aid if either country is attacked, during a Wednesday summit that came as both face escalating standoffs with the West.

The deal, which the leaders said covered areas including security, trade, investment, and cultural and humanitarian ties, could mark the strongest connection between Moscow and Pyongyang since the Soviet Union collapsed in 1991. Both leaders described it as a major upgrade of their ties.

The two met as Putin visited North Korea for the first time in 24 years. The summit came as the U.S. and its allies express growing concerns over an arms arrangement in which the country provides Moscow with badly needed munitions for its war in Ukraine in exchange for economic assistance and technology transfers that could enhance the threat posed by Kims nuclear weapons and missile program.

Kim said that the deal was the strongest ever treaty between the two nations, putting the relationship at the level of an alliance, and vowed full support for Russias war in Ukraine. Putin said that it was a breakthough document reflecting shared desire to move relations to a higher level.