Russian President Vladimir Putin has presented a car to his North Korean counterpart Kim Jong Un, North Korean state media said Tuesday, in another sign of warming ties between the two countries that have raised concerns in the United States.

The Russian-made car for Kim’s personal use was delivered Sunday by a Russian delegation, the state-run Korean Central News Agency (KCNA) reported.

Kim’s sister – and senior Pyongyang official – Kim Yo Jong thanked Putin on her brother’s behalf and said, “the gift serves as a clear demonstration of the special personal relations between the top leaders of the (North Korea) and Russia,” according to KCNA.

US intelligence officials are increasingly concerned about the long-term implications of what appears to be a new level of strategic partnership between North Korea and Russia, multiple officials familiar with the latest intelligence have told CNN.

Russia has repeatedly fired North Korean-supplied short-range ballistic missiles at Ukrainian targets in recent weeks. Meanwhile, US officials fear that North Korea may be able to use a tighter relationship with Russia to loosen China’s influence, potentially removing what some believe has been an important handbrake on Pyongyang’s nuclear testing program.

In January, high-ranking North Korean and Russian diplomats met in Moscow in advance of what North Korean state media says is a forthcoming visit to Pyongyang by Putin — his first in more than 20 years. And Kim visited Russia for a summit with Putin in September, where he endorsed the Kremlin’s war on Ukraine and said, “I will always be standing with Russia.”

Putin’s gift potentially violates United Nations sanctions imposed on North Korea for its nuclear weapons program, though the ban on luxury goods sales to the country has not prevented Kim from appearing in a range of high-end vehicles over the years.

The North Korean leader is often seen being chauffeured in what’s believed to be a Mercedes-Maybach Pullman Guard armored limousine, worth upwards of $1 million.

In 2018, he arrived at a meeting with US officials in a black Rolls-Royce. Earlier that year, two armored Mercedes-Maybach S600 Guard vehicles were shipped from the Netherlands to North Korea, likely for Kim’s use, according to the Washington-based Center for Advanced Defense Studies.

The center also reported that Pyongyang imported more than 800 luxury vehicles in the period from 2015 to 2017 alone – the majority originating from Russian companies.

During Kim’s visit to Russia last September, Putin showed the North Korean leader his limousine, made by Russian luxury automaker Aurus.

Former US President Donald Trump also gave Kim a viewing of the presidential Cadillac limousine nicknamed “the Beast” during their talks in Singapore in 2018.