WARSAW, Poland (AP) — A Polish government special commission has reinforced its earlier allegations that the 2010 plane crash that killed President Lech Kaczynski and 95 others in Russia was the result of Moscow’s assassination plan.

The latest of the commission’s reports, released Monday, alleges that an intentional detonation of planted explosives caused the April 10, 2010 crash of Soviet-made Tu-154M plane that killed Kaczynski, the first lady and 94 other government and armed forces figures as well as many prominent Poles.

Their deaths were the result of an “act of unlawful interference by the Russian side,” the commission’s head Antoni Macierewicz told a news conference.

“The main and indisputable proof of the interference was an explosion in the left wing … followed by an explosion in the plane’s center,” said Macierewicz, who in 2015-2018 served as defense minister in Poland’s right-wing government.

He denied that any mistakes were made by the Polish pilots or crew members, despite bad weather at the time of the crash.

The report repeats many previous allegations made by the commission, appointed by the government whose key figure is the main ruling Law and Justice party leader, Jaroslaw Kaczynski, the twin of the late president.

It comes at a time when Russia has unleashed a war on Poland’s neighbor Ukraine, and among the current tense relations between Warsaw and Moscow. Poland supports Ukraine in its struggle against Russia and is calling for very tough sanctions on Moscow for its Feb. 24 invasion of Ukraine.

The latest report once again drums up hostility toward Russia among some Poles, chiefly supporters of the nationalist government, it what seems to be an effort to consolidate the voter base of the Law and Justice party, which was founded by the Kaczynski twins in 2001.

Suspicions are additionally fuelled by Russia’s refusal to return the wreckage, which has complicated Poland’s investigation.

Earlier, two separate reports by Polish and Russian experts on aviation incidents said the crash on approach in dense fog to the Smolensk airport, which did not have sophisticated aviation equipment, was the result of human errors made in adverse weather conditions.

They found no proof of foul play.