MOSCOW — Suspicions among some in Poland that a 2010 plane crash that killed President Lech Kaczynski and much of the country’s senior leadership was not an accident were revived on Tuesday by a disputed newspaper report suggesting that traces of explosives may have been found in the wreckage in western Russia.

A spokesman for Poland’s military prosecutor dismissed the article as “sensationalist,” saying at a news conference on Tuesday that the highly sensitive equipment that experts used to examine the wreckage frequently yielded false positive results.

“It is not true that investigators found traces” of explosives, said the spokesman, Col. Ireneusz Szelag, who added that it might be as long as six months before conclusive test findings were available. “Evidence and opinions collected so far have in no way provided support to the belief that the crash was the result of actions of third parties, that is to say an assassination.”

Later in the day, the newspaper, Rzeczpospolita, partly retracted its report online, saying that the findings about the chemical traces were not as definitive as it had initially said.