The United States has accused Russia of providing advanced military assistance to Iran, including air defence systems, as it warned of deepening defence ties between Moscow and Tehran, with Russia using Iranian drones to hit targets in Ukraine.

White House National Security Council spokesman John Kirby cited US intelligence assessments for the allegations, saying Russia was offering Iran “an unprecedented level of military and technical support that is transforming their relationship into a full-fledged defense partnership”.

Washington has previously condemned security cooperation between Iran and Russia but on Friday described an extensive relationship involving equipment such as helicopters and fighter jets as well as drones, with the latter items resulting in new US sanctions.

Kirby said Russia and Iran were considering setting up a drone assembly line in Russia for the Ukraine conflict, while Russia was training Iranian pilots on the Sukhoi Su-35 fighter, with Iran potentially receiving deliveries of the plane within the year.

“These fighter planes will significantly strengthen Iran’s air force relative to its regional neighbours,” Kirby said.

Western powers have accused Iran of supplying drones to Russia for its war against Ukraine, as Moscow batters the country’s energy infrastructure in search of an advantage in the bloody conflict.

Kirby said the US would sanction three Russian-based entities active in “the acquisition and use of Iranian drones”.

The sanctions apply to the Russian Aerospace Forces, the 924th State Centre for Unmanned Aviation and the Command of the Military Transport Aviation.

“The United States will continue to use every tool at our disposal to disrupt these transfers and impose consequences on those engaged in this activity,” Secretary of State Antony Blinken said in a statement on the sanctions.

Last month, Tehran admitted it had sent drones to Russia but insisted they were supplied before Moscow’s Ukraine invasion.

‘Sordid deals’

The US also believes Iran is considering the sale of “hundreds of ballistic missiles” to Russia, Kirby said.

The United Kingdom’s foreign secretary James Cleverly took aim at the “sordid deals” between Moscow and Tehran, saying in a statement that Iran had sent drones to Russia in exchange for “military and technical support” from Moscow.

This “will increase the risk it poses to our partners in the Middle East and to international security,” Cleverly said, promising that “the UK will continue to expose this desperate alliance and hold both countries to account”.

For its part, Moscow has accused the West of supplying weapons to Ukraine that are ending up in the hands of bad actors, not only in Europe but also in Africa and the Middle East.

Russia’s ambassador to the United Nations, Vasily Nebenzya, referred to the recent comments by Nigeria’s President Muhammadu Buhari who said weapons and fighters from Ukraine were making their way to the Lake Chad region and helping violent groups.

Al Jazeera’s Kristen Saloomey said the UK’s ambassador to the UN, Barbara Woodward, did not directly address Nebenzya’s claims, which were made ahead of a UN Security Council meeting on Friday, but stated that Ukraine had a right to defend itself from Russia.

“She went on to say that the United Kingdom believes that buying weapons from Iran is in violation of international agreements and beyond the drones, she alleged that Russia is now trying to get ballistic missiles from Iran and also trying to make deals with countries like North Korea,” Saloomey said, speaking from the UN headquarters in New York.

‘Disappointing’ Merkel statement

Meanwhile, President Vladimir Putin said that any country that launches a nuclear attack on Moscow would be “wiped out” and that Russian weapons could forcefully respond.

He also expressed his disappointment at former German Chancellor Angela Merkel’s recent statements on Ukraine and on the Minsk agreements.

The parties to the Minsk agreements, which led to a ceasefire deal between Ukraine and Russian-backed separatists in eastern Ukraine in 2014 and 2015, had betrayed Russia by supplying Ukraine with weapons, Putin said.

In an interview published in Germany’s Zeit magazine on Wednesday, Merkel said the Minsk agreements had been an attempt to “give Ukraine time” to build up its defences.

Russia interpreted Merkel’s statements to mean that the Minsk peace plan was only concluded to give Ukraine time to arm itself and prepare for war with Russia.

“Honestly, this was absolutely unexpected for me. It’s disappointing. I frankly did not expect to hear something like this from the former German chancellor,” Putin told journalists in Bishkek, Kyrgyzstan.

“I have always assumed that the leadership of the federal republic of Germany would behave sincerely towards us,” Putin said.

“But it still seemed to me that the leadership of Germany was always sincere in its efforts to find a solution based on the principles that we agreed on and that were reached, among other things, in the framework of the Minsk process.”