NUSA DUA, Indonesia: Washington and allies said Wednesday they will investigate a deadly strike in Poland before deciding next steps, with United States President Joe Biden saying it was "unlikely" the missile was fired from Russia.
"We agreed to support Poland's investigation into the explosion," Biden told reporters after a hastily arranged gathering of allies on the sidelines of the Group of 20 (G20) in Bali, Indonesia.
"We're going to make sure we figure out exactly what happened... and then we're going to collectively determine our next step," added Biden after talks with the Group of Seven (G7) and other European leaders.
Asked if the missile, which killed two people in a village near the Ukrainian border, had been fired from Russia, Biden said there was "preliminary information that contests that".
"It's unlikely... that it was fired from Russia. But we'll see."
The explosion in Poland, a member of the North Atlantic Treaty Organization (Nato), immediately sparked concerns that the alliance might be drawn into Russia's nearly nine-month war against Western-backed Ukraine.
But the White House and allies have reacted cautiously, and Polish President Andrzej Duda also sought to calm tensions, saying there is no "unequivocal evidence" for where the missile came from and that he saw it as an "isolated" incident.
"Nothing indicates to us that there will be more," he said.
The foreign ministry earlier summoned Russia's ambassador to Warsaw to give "immediate detailed explanations" over the strike, and Poland is expected to request urgent consultations under Article 4 of the Nato Treaty on Wednesday.
Article 4 allows consultations to be called when any Nato member feels their "territorial integrity, political independence or security" are at risk.
- 'Slap in the face' -
Ukrainian President Volodymyr Zelensky quickly blamed Russia, which has launched a wave of missile strikes across the country that have left millions of households without power, calling the strike a "slap in the face" for the G20.
The incident will further expose fault lines in the group, which has struggled to find common ground on Russia's invasion of its neighbour, coming together to condemn the war's effects, but still divided on apportioning blame.
The summit has shown that even Russia's allies have limited patience with a conflict that has inflated food and energy prices worldwide and raised the spectre of nuclear war.
In a draft communique, Russia was forced to agree that the "war in Ukraine" -- which Moscow refuses to call a war -- has "adversely impacted the global economy".
It also agreed that "the use or threat of use of nuclear weapons" is "inadmissible", after months of President Vladimir Putin making such threats.
But Russia's G20 allies China, India and South Africa have so far refrained from publicly criticising Putin's war, and the draft joint statement is replete with diplomatic fudges and linguistic gymnastics.
Putin shunned the gathering, instead sending his pugnacious Foreign Minister Sergei Lavrov, who left the summit on Tuesday night, skipping the final day of talks.
The US and its allies have used the summit to broaden the coalition against Russia's invasion and scotch Moscow's claims of a war of East versus West.
Host Indonesia, meanwhile, has walked a tightrope, keen to end its G20 presidency with the relative triumph of a joint statement agreed by the fractured grouping.
It has declined to criticise Russia, and invited Zelensky to address the summit with a speech Tuesday in which the Ukrainian leader urged his counterparts to end the war and "save thousands of lives".
It was not immediately clear if the Poland strike would scupper the joint statement, which is due to be issued after leaders hold a final round of talks.
