Bali. US President Joe Biden on Tuesday vowed US support for an investigation into the explosion in Poland near the Ukrainian border that could escalate the ongoing Russia-Ukraine war into a regional conflict.

Speaking at a news conference in Indonesia’s resort island of Bali, Biden wasn’t able to confirm if the missile explosion had been fired from Russia.

“There is preliminary information that contests that. I don’t want to say that until we completely investigate. But it is — I — it’s unlikely, in the minds of the trajectory, that it was fired from Russia. But we’ll see,” Biden said per the transcript provided by the White House.

The US president was in Bali to attend the G20 Summit,

Poland is a member of security alliance NATO, which upholds a collective security principle in which an attack against one ally is considered an attack against all.

Earlier in the day, Biden met with the leaders of NATO and the G7 who were also in Bali following reports of the missile explosion that killed at least two people.

He also discussed the issue with Polish President Andrzej Duda and NATO Secretary General Jens Stoltenberg. 

“And we agreed to support Poland’s investigation into the explosion in rural Poland, near the Ukrainian border. And I’m going to make sure we figure out exactly what happened,” Biden said.

“And we also discussed the latest series of Russian missile attacks, which are continuing the brutality and inhumanity that they’ve demonstrated throughout this war against Ukrainian cities and civilian infrastructures. And they’ve been totally unconscionable, what they’re doing.”

He stressed that the US government will continue supporting Ukraine in this conflict.

“And the moment when the world came together at the G20 to urge de-escalation, Russia continues to — has chosen to escalate in Ukraine, while we’re meeting. I mean, there were scores and scores of attack — missile attacks into western Ukraine,” he said.

“We support Ukraine fully in this moment, and we have — we have since the start of this conflict. And we’re going to continue to do whatever it takes to give them the capacity to defend themselves.”

Russian Vladimir Putin didn’t attend the G20 Summit and appointed Foreign Minister Sergey Lavrov to lead the country’s delegation in Bali.

Lavrov cut short his mission and left for Russia on Tuesday.