Lviv, Ukraine   -  Russian missiles struck close to Lviv’s airport in Ukraine’s far west  Friday, extending the war to a relatively unscathed region near NATO territory, as China came under US pressure to restrain its Kremlin allies.

Ambulance and police vehicles raced to the scene of the early-morning strike on an aircraft repair plant near the border of NATO member Poland -- which has seen more than two million refugees cross over from Ukraine.

Motorists were turned away at checkpoints and a thick pall of smoke billowed over the airport, an AFP reporter saw, although officials said the plant was inactive and there were no fatalities.

Located 70 kilometres (45 miles) from the border, Lviv had until now largely escaped  assault by Russian forces, and it has become a rear base for foreign diplomats fleeing Ukraine’s capital Kyiv.

“This was a strike on the city of Lviv, on a humanitarian hub where more than 200,000 people have been displaced,” regional governor Maksym Kozytsky told reporters.  Valentin Vovchenko, 82, told AFP in Lviv: “We fled Kyiv because of the attacks but now they’ve started to hit here.”

As President Vladimir Putin’s three-week-old ground offensive has stalled under fierce Ukrainian resistance, Moscow has increasingly turned to indiscriminate air and long-range strikes.

In the besieged southern city of Mariupol, rescue workers have been searching for any survivors buried beneath the rubble of a bombed-out theatre, amid fears hundreds may be trapped.

Russia said its troops and their separatist allies were fighting in the centre of the strategic port city.

Authorities in Kyiv said one person was killed when a downed Russian rocket struck a residential building in the capital’s northern suburbs. They said a school and playground were also hit.