Biden convened a meeting of several leaders gathered in Bali, Indonesia, for a G20 summit to discuss the incident. Leaders from NATO members Germany, Canada, Netherlands, Spain, Italy, France and Britain attended, as well as non-NATO member Japan and representatives from the European Union.
Asked whether it was too early to say if the missile was fired from Russia, Biden said, "There is preliminary information that contests that. I don't want to say that until we completely investigate it, but it is unlikely in the lines of the trajectory that it was fired from Russia but we’ll see.”
The United States and NATO countries would fully investigate before acting, Biden said.
NATO ambassadors are expected to meet later on Wednesday.
Poland has said what was probably a “Russian-made missile” fell on a village in the country’s east killing two people, but that there was “no concrete evidence” on who had fired it, as its NATO allies prepared to hold an emergency meeting to discuss the strike.
The Polish foreign ministry said the weapon fell on Przewodow, about six kilometres (3-1/2 miles) from the border with Ukraine, with the country convening a meeting of its national security council, Al Jazeera reported. Poland’s foreign ministry said the strike took place at about 3.40 pm (14:40 GMT) on Tuesday.
According to US officials, initial findings suggested that the missile that hit Poland was fired by Ukrainian forces at an incoming Russian missile, the Associated Press said.
Earlier, Polish President Andrzej Duda had told reporters it was "most likely a Russian-made missile", but there was no concrete evidence of who fired it, and the incident was a one-off.
Russia's defence ministry denied that any Russian missiles hit Polish territory, describing such reports as "a deliberate provocation aimed at escalating the situation". Kremlin spokesperson Dmitry Peskov said he had no information on an explosion in Poland.
Any Russian strike on Poland could risk widening the conflict between Russia and Ukraine as members of the North Atlantic Treaty Organization (NATO) are committed to collective defence under its Article 5.
ZZ/PR