Chief of the Security Service of Ukraine (SBU) Valentyn Nalyvaichenko will visit the U.S. next week to present proof of Russian aggression against Ukraine in the U.S. Congress.

"The first day [of the visit] will be in the Senate, the second – in the House of Representatives, where I will present proof of Russian aggression and go back," Nalyvaichenko said at a roundtable talk on battling corruption, which was held in Kyiv on Friday.

"There will be hearing in the Senate and Congress ext week. And in addition to the proof of Russian aggression that we'll present, we'll also have a serious talk about the cooperation with the FBI and the money laundering issues," the SBU Chief said.