U.S. intelligence has assigned more than 1,000 spies to Olympic security as part of a highly classified effort to protect the Rio 2016 Summer Games and American athletes and staff, NBC News has learned.

Hundreds of analysts, law enforcement, and special operations personnel are already on the ground in Rio de Janeiro, according to an exclusive NBC News review of a highly classified report on U.S. intelligence efforts.

In addition, more than a dozen highly trained Navy and Marine Corps commandos from the U.S. Special Operations Command are in Brazil, working with the Brazilian Federal Police and the Brazilian Navy, according to senior military officials.

The U.S. military, as expected, has placed larger military units on call should a rescue or counterterrorism operation be needed, the officials said.

The classified report outlines an operation that encompasses all 17 U.S. intelligence agencies, including those of the armed services, and involves human intelligence, spy satellites, electronic eavesdropping, and cyber and social media monitoring.

Areas of cooperation include vetting 10,000-plus athletes and 35,000-plus security and police personnel and others; monitoring terrorists’ social media accounts; and offering U.S. help in securing computer networks, the review shows.

“U.S. intelligence agencies are working closely with Brazilian intelligence officials to support their efforts to identify and disrupt potential threats to the Olympic Games in Rio,” said Richard Kolko, a spokesman for National Intelligence Director James Clapper.

Read More: NBC

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