CIA Director Mike Pompeo on Thursday defended his decision to meet with officials from the Russian intelligence service last week, arguing that there was nothing “untoward” about the meeting.

Reports surfaced this week revealing that Pompeo met with the chief of the Russian Foreign Intelligence Service, Sergey Naryshkin, who is on the U.S. sanctions list, when he came to the U.S.

The CIA has acknowledged that the meeting with Russian officials took place, but did not reveal which Russian officials attended the meeting. In his letter defending the meeting, Pompeo did not specifically confirm that he met with Naryshkin.

Pompeo’s defense came in the form of a letter to Minority Leader Chuck Schumer (D-NY), who on Tuesday questioned why U.S. officials met with their Russian counterparts in the U.S.

In a speech on the Senate floor about the Trump administration’s missed deadline to impose new sanctions on Russia, Schumer brought up reports that the Russian spy chiefs met with U.S. intelligence officials and called it an “extreme dereliction of duty by President Donald Trump.”

“This is a serious national security issue. Russia hacked our elections. We sanctioned the head of their foreign intelligence, and then the Trump Administration invites him to waltz through our front door,” Schumer said. “This is an extreme dereliction of duty by President Trump, who seems more intent on undermining the rule of law in this country than standing up to Putin.”

Pompeo singled out Schumer for suggesting “there was something untoward in officials from Russian intelligence services meeting with their U.S. counterparts.”

“Let me assure you there is not,” Pompeo wrote.

The CIA chief added that U.S. officials sometimes meet with Russian intelligence counterparts in order to “work together on issues such as aviation security and preventing foreign fighters returning to both Russia and America.’

“When those meetings take place, you and the American people should rest assured that we cover very difficult subjects in which American and Russian interests do not align,” he added. “Neither side is bashful about raising concerns relating to our intelligence relationships and the interests of our respective nations. We vigorously defend America in these encounters and pull no punches — we never will.”

Read the full letter from Pompeo: