U.S. President Joe Biden, center, Canadian Prime Minister Justin Trudeau, left, and British Prime Minister Rishi Sunak attend an emergency meeting of leaders at the G20 summit following the overnight missile strike by a Russian-made rocket on Poland, Wednesday, Nov. 16, 2022, in Nusa Dua, Bali, Indonesia. AP
Foreign ministry spokeswoman Mao Ning told a regular press briefing: "Under the current situation, all relevant parties should stay calm and exercise restraint to avoid escalation of the situation."
US President Joe Biden said earlier it was "unlikely" the missile had been fired from Russia, which invaded Ukraine in February, while France urged "utmost caution" in identifying who was behind the blast.
On the sidelines of the G20 summit in Indonesia's Bali, Western leaders held an "emergency roundtable" where they urged against jumping to any conclusions about the origins of the strike.
The talks came after Poland's President Andrzej Duda said there was no clear evidence of who fired the missile that killed two people in the southeastern village of Przewodow.
China is a key ally of Russia and has not openly condemned its military campaign in Ukraine.