Russia could use non-conventional weapons, West fears

Western officials have said they are "very concerned" about the risk of escalation in the war between Russia and Ukraine.

They are particularly concerned about the possibility of Russia using non-conventional weapons, they say.

This most likely refers to chemical weapons although the term also covers tactical (small-scale) nuclear weapons, biological weapons and dirty bombs.

"We've got good reason to be concerned," said one Western official.

They said this was partly because of what had been seen in other places where Russia has been engaged in conflict, notably Syria where chemical weapons were used by its allies.

Officials also pointed to some of the disinformation and claims coming from Russia as potentially "setting the scene" for some kind of "false flag" claim that the Ukrainians had used them - or developed weapons.

In a tweet, the Russian Embassy referred to claims made by their foreign ministry spokeswoman that "recently found documents" showed components of biological weapons were made in Ukrainian laboratories - with funding from the US Department of Defense.

Russian officials and media have also claimed in recent days that Ukraine was planning to build a so-called dirty bomb - which disperses radioactive material.

Meanwhile Russia's foreign minister has claimed Ukraine had been seeking nuclear weapons.

Some believe Moscow is pushing these claims to come up with a justification for its own public about why it invaded Ukraine.