"In this case, I will definitely stay in the National Security and Defence Committee but will withdraw from the parliamentary probe that will be completed by May 1," Kasčiūnas told journalists at the parliament on Thursday.
The politician said he would suspend from the probe when it examines materials in connection to the political corruption case.
After meeting with Prime Minister Saulius Skvernelis earlier on Thursday, Parliamentary Speaker Viktoras Pranckietis pledged to turn to the committee with a request to check whether Kasčiūnas can stay in the committee.
On Wednesday, Lietuvos Rytas daily said that Irena Degutienė, conservative vice-chairperson of the Lithuanian parliament, had been questioned by the Special Investigation Service about Kasčiūnas who had not yet won the Seimas mandate. He was then working as Degutienė's adviser.
According to the daily, the authorities suspected that Kasčiūnas, in return for support to an association, had been asked by Kurlianskis to persuade Degutienė, a long-standing member of the parliamentary Budget and Finance Committee, to vote in support of an amendment on consumer loans initiated by Liberal MP Šarūnas Gustainis.
The article also mentions testimony by the conservatives' leader Gabrielius Landsbergis who had met with Kurlianskis on a few occasions.
Kasčiūnas was questioned as a witness in the case where suspicions were brought against the Liberal Movement's former leader Eligijus Masiulis, MP Gintaras Steponavičius, Šarūnas Gustainis, former Labor Party's MP Vytautas Gapšys and MG Baltic's former vice-president Kurlianskis along with three legal entities, namely, the Liberal Movement, the Labour Party and MG Baltic.