In a wide-ranging interview with PBS NewsHour’s Judy Woodruff, former Director of National Intelligence James Clapper addressed Trump’s handling of classified information, and he called recent reports that the president’s son-in-law Jared Kushner had requested a secret back channel to Russian government officials “curious.”

“Why all the cloak-and-dagger secrecy?” Clapper said. “If the intent was simply to reach out to establish — to make acquaintance, one wonders if there is something worse than that or more nefarious than that.”

Though attempts to establish back channels are not new, Clapper said it’s unusual to set up such a channel at an embassy or other secure location controlled by a foreign government.

“I’m not aware of any arrangement like that or attempts to make arrangements like that in the past,” he said.

Clapper added that reports of such contacts raise red flags when considered alongside Russia’s interference in the 2016 U.S. presidential election. Russia’s alleged interference in the U.S. election was “a slick, sophisticated propaganda campaign clearly oriented toward hurting Secretary Clinton and helping now-President Trump,” Clapper said.

“In that context, then for these interactions to go on with our primary adversary, the Russians, was of great concern.”

“In the context of this aggressive and multifaceted campaign that the Russians mounted to interfere with the election,” Clapper told Woodruff, “not just the hacking, but social media trolls, fake news… In that context, then for these interactions to go on with our primary adversary, the Russians, was of great concern.”

Clapper, who resigned Jan. 20, said that while he was still in government, he had no knowledge of the Trump campaign’s alleged outreach to the Russians.

Woodruff also asked Clapper about a report from the Circa news website, which stated that the National Security Administration under the Obama presidency “routinely violated American privacy protections while scouring through overseas intercepts,” according to FISA court documents. Clapper said the violations were “human errors, but certainly not a conspiracy to abate people’s privacy. And certainly the White House had nothing to do with any of that.”

The interview also touched on critical national security issues like the North Korean nuclear program and new sanctions against the Iranian government, as well as President Trump’s outreach to Sunni allies in the fight against ISIS.