Moscow has a history of falsely accusing its opponents of staging "provocations" which either never happened at all, or were subsequently carried out by themselves or their allies.
What has Moscow said?
A Russian Ministry of Defence briefing on 11 May asserted that Ukrainian forces had "carried out an explosion of a tanker with fertiliser, presumably ammonium nitrate, which resulted in a cloud of orange smoke that dissipated after some time".
According to Moscow, the aim of the explosion, which occurred in the Kharkiv region, was to accuse Russia of using chemical weapons in order to "extract additional military aid from the West by the Kyiv regime".
No evidence was given in support of the claim that Ukrainian forces were responsible for the explosion.