Chinese warships started exercises in the Baltic Sea for the first time on Tuesday, conducting a joint drill with Russia in a further sign of how the two countries are expanding their global reach through ever-closer military co-operation.

China and Russia have stressed that Joint Sea 2017 is just the latest in a series of regular joint manoeuvres. But the Baltic states and Poland are unsettled by Russia, which they accuse of regular military provocation close to their borders, conducting exercises on their doorstep alongside a quasi-ally.

Following a simulation exercise last weekend, three Chinese and 10 Russian warships, as well as aircraft and helicopters, began practising live-fire combat against submarines, other warships and aircraft, the two militaries said.