Russia has issued its bluntest warning yet that it is prepared to respond with force if its interests in Ukraine come under attack, much as it did in Georgia six years ago.

The warning from Sergei Lavrov, the veteran foreign minister, came after authorities in Kiev announced the relaunch of an “anti-terrorist operation” against pro-Kremlin rebels in the east of the country.

“If we are attacked, we would certainly respond,” Mr Lavrov said. “If our interests, our legitimate interests, the interests of Russians have been attacked directly, like they were in South Ossetia for example, I do not see any other way but to respond in accordance with international law.”

Mr Lavrov did not elaborate, but the reference to South Ossetia strongly hinted at the