U.S. National Security Advisor Jake Sullivan talked with his counterpart in Poland on Tuesday regarding reports that two Russian missiles landed in the NATO ally’s territory, killing two people.

Adrienne Watson, the White House National Security Council spokesperson, confirmed Sullivan’s talk with Jacek Siewiera, chief of Poland’s national security bureau, in a tweet, but added “we cannot confirm the reports or any of the details at this time.”

The missiles strayed into Polish territory 15 miles from the Ukraine border during a Russian barrage on Ukraine energy facilities, according to The Associated Press. If true, it would be the first time Russian weapons have landed in a NATO country since it invaded Ukraine in February.

The AP reported the Russian Defense Ministry denied “any strikes on targets near the Ukrainian-Polish border” and said in a statement that photos of purported damage “have nothing to do” with Russian weapons.

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