Vladimir Putin promised to build trade and security systems with North Korea that are not controlled by the West and pledged his unwavering support in a letter published by North Korean state media on Tuesday ahead of his planned visit to the country.

In the letter, printed in North Korea’s Rodong Sinmun, the ruling Workers’ Party mouthpiece, the Russian president said the two countries have developed good relations and partnerships over the past 70 years based on equality, mutual respect and trust, Reuters reported.

“We will develop alternative mechanisms of trade and mutual settlements that are not controlled by the West, and jointly resist illegitimate unilateral restrictions,” Putin wrote.

“And at the same time – we will build an architecture of equal and indivisible security in Eurasia.”

He thanked North Korea for supporting what Russia calls its special military operation in Ukraine, and vowed support for Pyongyang’s efforts to defend its interests despite what he called “U.S. pressure, blackmail and military threats”.

The article was published a day after the two countries announced that Putin would visit North Korea for the first time in 24 years for two days starting on Tuesday.

Putin’s foreign policy adviser Yuri Ushakov said Russia and North Korea may sign a partnership agreement during the visit that would include security issues.

Russian Defence Minister Andrei Belousov, Foreign Minister Sergei Lavrov, the ministers for natural resources, health, and transport, the heads of the Russian space agency and its railways, and Putin’s point man for energy, Deputy Prime Minister Alexander Novak, will be part of the delegation.

The visit will include one-on-one discussions between the two leaders, as well as a gala concert, state reception, honor guards, document signings, and a statement to the media, Assistant to the Head of State Yuri Ushakov told reporters, according to Russia’s Interfax news agency.

Ahead of the visit North Korea appears to have been making preparations for a possible military parade in downtown Pyongyang, commercial satellite imagery showed.

The summit presents the greatest threat to U.S. national security since the Korean War, said Victor Cha, a former U.S. national security official now with the Center for Strategic and International Studies, Reuters reported.

“This relationship, deep in history and reinvigorated by the war in Ukraine, undermines the security of Europe, Asia, and the U.S. homeland,” he wrote in a report on Monday.

He called on Washington to work with Europe and other partners to increase economic and diplomatic pressure on Pyongyang, engage with China, and launch a major human rights and information campaign to flood the reclusive North with outside media.