The Ukrainian military said a soldier was killed and another seriously wounded in artillery fire from Russia-backed separatist rebels, as hostilities rose sharply in the east of the country. As of the reported attack on Sunday, Ukraine says 27 soldiers have been killed in the east this year, more than half the number who died in all of 2020. Attacks have intensified in recent weeks and Russia has built up troops along the Ukraine border. Russia denies western claims that it has sent troops into eastern Ukraine to help the rebels, but officials say the army could intervene if Ukraine tries to retake the area by force. The military buildup has raised sharp concerns in the west. Antony Blinken said on Sunday: “If Russia acts recklessly, or aggressively, there will be costs, there will be consequences.” The US secretary of state told NBC’s Meet the Press: “I have to tell you I have real concerns about Russia’s actions on the borders of Ukraine. That’s why we’re in very close contact, in close coordination, with our allies and partners in Europe. All of us share that concern.” Ukrainian forces and Russia-backed separatists have been fighting in eastern Ukraine since shortly after Moscow’s 2014 annexation of Ukraine’s Crimean peninsula. More than 14,000 people have died in the conflict, and efforts to negotiate a political settlement have stalled. The Kremlin, which has not denied the troop movements, said on Sunday it was not moving towards war with Ukraine – but also that it would “not remain indifferent” to the fate of Russian speakers in the conflict-torn region. The White House this week said the number of Russian troops at the border with Ukraine was greater than at any time since 2014. Fighting has subsided in the past few years but a diplomatic solution to settle the eastern regions’ status has remained out of reach. Crimea is still recognised as part of Ukraine by the United Nations, and Kiev has vowed to one day win it back. Joe Biden, who previously oversaw Washington’s policies on Ukraine, is viewed as a strong ally by Ukrainians. Blinken, his top diplomat, agreed on supporting Ukraine against “Russian provocations”, in talks this week with his French and German counterparts.