The National Football League and National Hockey League in the U.S. both issued statements Saturday declaring heightened security alerts at scheduled games, in the wake of the Paris terror attacks that took 129 lives on Friday night. At Sunday's 13 scheduled football games, NFL stadiums will have "increased security and law enforcement presence," with clubs being informed ahead of time of the upgraded security.

The NHL also issued a statement on security at its games. "We have sent an advisory to our clubs to be on heightened alert given today's events in Paris," Deputy Commissioner Bill Daly said Friday. Thirteen NHL games are scheduled for Saturday and two on Sunday.

Earlier Saturday, it emerged that one of the Paris attackers had a ticket to the France-Germany soccer game at the Stade de France. The attacker attempted to enter the stadium, but was blocked by security officials when an explosives vest was discovered during a frisk. Police officials said the attacker apparently wanted to detonate inside the stadium to cause a deadly stampede.

"Following the events in Paris on Friday, we are closely monitoring events and have been in communication with the Department of Homeland Security and the FBI, which have informed us that there are no known threats against NFL stadiums," the statement said. The NFL is also recommending that fans not take bags with them to games, requesting if visitors need to, they should be made of a clear material and not exceed 12-by-6-by-12 inches.

The NFL's practices, in place before the heightened measures were announced Saturday, have been approved by the Department of Homeland Security since 2008 as "effective antiterrorism technology," with all clubs using perimeter security and metal detectors.