The U.S. House of Representatives has opened a probe into allegations that investment bank Credit Suisse instructed clients to destroy documents allegedly related to sanctions on Russian oligarchs. Credit Suisse CEO Thomas Gottstein, however, insists that there is no concern that wrongdoing will be discovered.

In an interview with CNBC on Wednesday, Gottstein said that the letter with alleged instructions to “destroy and permanently erase” documents related to a portfolio of loans backed by yachts and private jets potentially owned by Russian oligarchs was not done to dodge any sanctions on the bank. For this reason, he insisted that the U.S. probe will “absolutely not” provide evidence to support this charge.

“This was a one-off transaction, which was very much a continuation of three other securitized transactions we did before," Gottstein told CNBC.

“It was part of our dealing with private placement investors, institutional investors, and there were absolutely no materials in there that were relevant from a sanctions perspective,” he added.

News of Credit Suisse's instruction to investors to destroy documents linked to Russian oligarchs' loans for yachts first emerged with a report by the Financial Times last month. The story came as Credit Suisse began moving to reduce its more than $2 billion exposure to Russia as Switzerland joined the U.S., United Kingdom and European Union in sanctioning Russia for its invasion of Ukraine in February.

Credit Suisse maintained that its request was simply “good housekeeping” that had nothing to do with either the war or sanctions that followed. But the U.S. House Oversight Committee was more skeptical, prompting it to send a letter on March 28 to request documentation related to this decision.

"Given the timing of this request and its subject matter, Credit Suisse’s action raises significant concernsthat it may be concealing information about whether participants in the securitization deal...may be evading sanctions imposed by the United States and the international community in response to Russia’s unprovoked and unjustified invasion of Ukraine," wrote Oversight Chairwoman Rep. Carolyn Maloney, D-NY., and Rep. Stephen F. Lynch, D-Mass., in their letter.

The lawmakers requested that Credit Suisse provide this documentation by April 11. It has not yet been confirmed whether the bank has provided this information to Congress.

Credit Suisse is only one of several Western banks that have operated in Russia but are working to reduce their exposure to the country. Gottstein insisted in his CNBC interview that the bank will take on no new Russian clients and that it was continuing to unwind its operations in the wake of the war.