Russia announced new military exercises Thursday involving ground and air forces near its border with Ukraine, swiftly responding to a Ukrainian operation to drive pro-Russia insurgents out of occupied buildings in the country's tumultuous east. The Ukrainian move, which killed at least two people, brought new threats from Russian President Vladimir Putin, who denounced it as a "punitive operation." Russia's foreign minister warned a day earlier that any attack on Russian citizens or interests in eastern Ukraine would bring a strong response.