Russia carries out second nuclear training exercise in two weeks

Russia is carrying out a new nuclear training exercise, President Vladimir Putin has said.

Speaking to military leaders by video call, Mr Putin declared there would be "another exercise of strategic deterrence forces" on Tuesday - two weeks after the last.

The previous drill took place on 18 October in Tver, northwest of Moscow, using ballistic missiles capable of striking US cities.

"We will work out the actions of officials to control the use of nuclear weapons with practical launches of ballistic and cruise missiles," Mr Putin said on Tuesday.

According to state media, the Russian leader said that although nuclear weapons would be a "last resort", the Kremlin needs to stand ready to use them.

"I stress that we are not going to get involved in a new arms race, but we will maintain nuclear forces at the level of necessary sufficiency," he added.

It comes as North Korea's foreign minister Choe Son Hui arrived in Russia on Tuesday - landing in the far east of the country on the way to Moscow.

Russian state media report that Ms Choe has no plans to meet Mr Putin while she is in the country - and it is not clear which officials she will hold talks with.

Neither Mr Putin nor Ms Choe have commented on US, NATO, and South Korean claims that thousands of North Korean troops have been sent to Russia to train them to fight in Ukraine.

US intelligence officials claim to have evidence that at least 3,000 North Korean troops are inside Russia. The US says Pyongyang has already sent arms to Kremlin forces.

Ukrainian President Volodymyr Zelenskyy says he has intelligence showing as many as 10,000 North Korean soldiers preparing to cross the Russian border.

White House national security spokesman John Kirby says the US believes soldiers travelled from the Korean peninsula to Russia's Pacific port of Vladivostok earlier this month.

The South Korean intelligence community says North Koreans are in Russia to be trained to use drones and other equipment in its fight against Ukraine.

Lack of denial causing concern

Mr Putin's lack of denial is worrying both Ukraine and international observers.

It has seen Mr Zelenskyy demand more weapons and provide an international plan to keep Kremlin forces at bay.

These fears have been further compounded by Mr Putin's amendment to Russia's nuclear doctrine last month. He said Russia could use nuclear weapons if it is attacked by any state with conventional missiles.

In a thinly veiled warning to the West over its support of Ukraine, the Kremlin leader also said he would consider any assault that was supported by a nuclear power to be a joint attack on Moscow.

Meanwhile, Washington has said it will not impose any fresh restrictions on the use of its weapons against North Korea should there be evidence of their personnel being used in Ukraine.

South Korean president Yoon Suk Yeol, meanwhile, last week raised the possibility of supplying Ukraine with weapons while saying Seoul is preparing countermeasures that could be rolled out in stages depending on the degree of military cooperation between Pyongyang and Moscow.