The UK is seeking to keep core state functions running and mitigate financial pressures caused by Russia’s invasion, Johnson’s office said.
Britain has sought a central role in the international response to Russia’s invasion of Ukraine by providing defensive military aid, arguing for tougher sanctions again the Kremlin and offering financial support.
Nevertheless, Johnson’s government has faced criticism that its sanctions have been too slow and its refugee programme underwhelming.
The latest round of cash, which is in addition to $290.95 million (220 million pounds) pledged already, could be used to pay public-sector workers in Ukraine or fund pension and social security payments, British authorities said.