Polish opposition politician Jaroslaw Kaczynski is set to seek U.S. help in investigating the plane crash in western Russia, in which his twin brother, then president Lech Kaczynski, died in April, RIA Novosti reported.
Kaczynski, a losing candidate in early presidential elections that followed the death of his brother, has repeatedly criticized incumbent President Bronislaw Komorowski and his administration for their failure to investigate the air disaster properly.
This time, Kaczynski wrote a letter to U.S. congressmen, seeking their help in investigating the plane crash near the western Russian city of Smolensk, in which Polish first couple and many top state officials were killed.
Members of Kaczynski's conservative Law and Justice party will deliver the letter during their visit to the United States.
The initiative has already provoked fury from the country's leadership.
"This is absolutely scandalous, on the verge of treason," government spokesman Pawel Gras told the Zet Radio, also calling the initiative "inadmissible."
Presidential aide Tomasz Nalecz said, in his turn, that Kaczynski's party was "playing with fire."
The country's former foreign minister, Anna Fotyga, who will be in the Polish delegation to deliver the letter, said her trip to the U.S. came as "a response to a U.S. initiative." The visit is scheduled for mid-November.
The worn-out Tu-154 with a top-level Polish delegation crashed near the western Russian city of Smolensk in thick fog on April 10, killing all 96 people onboard. The delegation was on its way to a commemoration ceremony of the 1940 Katyn massacre, in which more than 20,000 Poles were executed by Soviet forces.
Kaczynski has earlier called on the Polish and Russian governments to assume full responsibility for "completely abandoning" the investigation into the air disaster and urged the president and Prime Minister Donald Tusk to step down.