Russia to make false claim at the UN that Ukraine is about to drop 'dirty bomb'

Russia is to make spurious claims that Ukraine will drop a 'dirty bomb' to the United Nations Security Council, according to reports.

Vasily Nebenzya, the nation's permanent representative on the council, will call on the UN's chief secretary Antonio Guterres to do "everything in his power" to prevent a nuclear-laced weapon being used by Kyiv - despite presenting no evidence so far they are planning to do so.

"We will regard the use of the "dirty bomb" by the Kiev regime as an act of nuclear terrorism," he wrote in a letter seen by Reuters on Monday.

"We urge the Western countries to exert their influence on the regime in Kiev to abandon its dangerous plans threatening international peace and security,"

A Russia letter to UN General Antonio Guterres (pictured) will ask him to 'do everything in his power' to stop Kyiv's supposed threat (AFP via Getty Images)

It comes after top Russian officials spent the past two days making rare calls to Western powers to accuse Ukraine of preparing a weapon containing nuclear material.

The Ministry of Defence confirmed on Sunday that defence secretary Ben Wallace had spoken with his Russian counterpart Sergei Shoigu following a request from the Kremlin, where it was alleged "Ukraine was planning actions facilitated by Western countries" to "escalate the conflict in Ukraine".

A statement added that Wallace had "refuted these claims" and "cautioned that such allegations should not be used as a pretext for greater escalation."

It follows two days of rare calls from Russia to Western powers making the unfounded allegations (AFP via Getty Images)

Russia has also told council counterparts it will bring up the same issue during a closed-door meeting on Tuesday, diplomats said.

Ukrainian President Volodymyr Zelenskiy has responded by accusing Russia of planning such an attack itself to blame on Ukraine.

Britain's mission to the United Nations posted on Twitter late on Monday: "Reminder: Ukraine has no nuclear weapons."

Ukraine believes Russia may be making the claims as a pretext to an attack of its own (AFP via Getty Images)

Earlier on Monday, U.N. spokesman Stephane Dujarric said: "All parties should avoid any actions that could lead to miscalculation and escalation of what's already a devastating conflict."

While the U.N. Security Council has met on a number of occasions since the outbreak of hostilities in February, its actions have been limited as Russia one of the veto-powers, along with the United States, China, Britain and France.

Earlier this month, 143 countries on the 193-member UN General Assembly voted to condemn Russia's "attempted illegal annexation" of four partially occupied regions in Ukraine, and called on all countries not to not recognise the move.