Seoul | The foreign ministers of Russia and North Korea hailed their countries' deepening cooperation during talks in Pyongyang on Thursday, days after the United States said the North had transferred munitions to Russia to boost its warfighting capabilities.

Russian Foreign Minister Sergey Lavrov flew to Pyongyang on Wednesday for a two-day trip.

During a reception speech later in the day, Lavrov said he thanked North Korea for its strong support for Russia's war on Ukraine.

The focus of outside attention to Lavrov's visit is whether the two countries would provide any hints of how they would solidify their security cooperation or announce the timing for Russian President Vladimir Putin's promised trip to Pyongyang to reciprocate North Korean leader Kim Jong Un's visit to Russia's Far East last month.

During his travel to Russia, Kim met Putin at the Vostochny Cosmodrome, Russia's most important domestic space launch centre, and inspected other key Russian weapons-making sites.

That triggered intense speculation that Kim seeks sophisticated Russian technologies to modernise his nuclear arsenal in return for supplying conventional arms to refill Russia's exhausted weapons inventory.

Neither Russian and North Korean governments has disclosed what steps Putin and and Kim agreed during the summit.

“After the historic summit between President Putin and Chairman of State Affairs Kim Jong Un at the Vostochny Cosmodrome on September 13, we can confidently say that the relations have reached a qualitatively new strategic level,” Lavrov said at the start of his meeting with North Korean Foreign Minister Choe Sun Hui on Thursday, according to Russia's state-run Interfax news agency.

Choe said her meeting with Lavrov “will become an important stage in terms of the implementation of the agreements” reached by Kim and Putin, Russia's state-run Tass news agency reported.

It cited Choe as saying that frequent meetings between the two countries' top diplomats prove that bilateral ties are developing “vigorously.” North Korea's state media hasn't reported about the meeting.

During a dinner banquet held for him, Lavrov said Russia deeply values North Korea's “unwavering and principled support” for its war on Ukraine as well as Pyongyang's decision to recognise the independence of Russian-backed separatist regions in eastern Ukraine, according to Russia's Foreign Ministry.

“We are fully aware that many countries worldwide share similar viewpoints and assessments, but only a select few, such as (North Korea), explicitly declare their solidarity with Russia and can express it openly,” Lavrov said.

According to North Korea's state media, Lavrov also praised North Korea for "remaining unfazed by any pressure of the US and the West,” and said that Russia fully supports Kim's push to protect its security and economic interests.

Choe said that Pyongyang and Moscow were building an “unbreakable comradely relationship” under the leadership of Kim and Putin.

The recently flurry of diplomacy between Moscow and Pyongyang underscores how their interests are aligning in the face of their separate, intensifying confrontations with the United States — North Korea over its advancing nuclear program and Russia over its war with Ukraine.

The White House said Friday that North Korea had delivered more than 1,000 containers of military equipment and munitions to Russia.

Such an arms shipment would violate UN Security Council resolutions that bans any weapons trading involving North Korea.

The White House released images that it said show the containers were loaded onto a Russian-flagged ship before being moved via train to southwestern Russia.

The containers were shipped between September 7 and October 1 between Rajin, North Korea, and Dunay, Russia, according to the White House.

Since last year, the US has accused North Korea of providing ammunition, artillery shells and rockets to Russia, likely much of them copies of Soviet-era munitions.

North Korea has steadfastly denied it shipped arms to Russia, but South Korean officials said North Korean weapons provided to Russia had already been used in Ukraine.

Lim Soosuk, spokesperson of South Korea's Foreign Ministry, told reporters Thursday that Seoul was closely monitoring Lavrov's visit to North Korea and said that any cooperation between Moscow and Pyongyang should be conducted in a way that complies with UN Security Council resolutions.

When asked whether Lavrov's comments stating that Russia fully supports Kim's policies could be interpreted as an acceptance of North Korea's nuclear nuclear weapons status, Lim insisted that the North “no matter what it does, will never be recognised as a nuclear power and will face increasing international sanctions.”