Russia and China pose the biggest espionage and cyberattack threats to the United States and are more aligned than they have been in decades, the leader of the U.S. intelligence community told U.S. senators on Tuesday.

While the two countries seek to expand their global reach, Director of National Intelligence Dan Coats said, some American allies are pulling away from Washington in reaction to changing U.S. policies on security and trade.

"China, Russia, Iran, and North Korea increasingly use cyberoperations to threaten both minds and machines in an expanding number of ways — to steal information, to influence our citizens, or to disrupt critical infrastructure," Coats said.