The U.S. State Department has issued a warning to Americans traveling this summer to France to beware of terrorist threats at sporting events, following the discovery of an ISIS plot to attack soccer stadiums during a tournament that kicks off June 10 in Paris.

The terror group’s new focus on sporting events also raises domestic alarms. This year, the popular U.S. Open tennis tournament in New York coincides with the 9/11 anniversary.

French intelligence says it uncovered plans to attack the European Soccer Championship after searching the laptop used by Saleh Abdeslam, one of the Paris terrorists. Investigators found photos of French cities where the tournament will be held, along with notes citing the use of suicide bombs, assault rifles and even drones to carry out attacks inside stadiums that seat 80,000-plus spectators.

France is hosting the widely televised Euro Championship, which kicks off next week in the previously targeted Stade de France in Paris and runs through July 10.

More than 2.5 million fans are expected to turn out at 10 stadiums across Europe for the 51 soccer matches involving 24 countries at Euro 2016. Major cities will also provide “fan zones” for crowds watching games on big screens outside stadiums.

“Euro Cup stadiums, fan zones and unaffiliated entertainment venues broadcasting the tournaments in France and across Europe represent potential targets for terrorists, as do other large-scale sporting events and public gathering places throughout Europe,” the State Dept. warned American tourists in a new advisory.

State had planned to end its previous European travel alert, prompted by March’s ISIS attacks in Brussels, on June 20. But the agency decided to extend the alert through Aug. 31 after French and U.S. intelligence picked up increased chatter among jihadist networks approaching the summer sporting events.

France has extended its state of emergency through July 26 to cover the period of the soccer cup, as well as the Tour de France cycling race held July 2-24.

Germany has also heightened its threat conditions for ISIS strikes.

“We know that ISIS has the European Championship in its sights,” German domestic intelligence chief Hans-Georg Maassen said.

Meanwhile, the head of Europol warned that terror cells across Europe are stockpiling explosives to carry out “large-scale home attacks.”

Last year, ISIS terrorists slaughtered 130 people across Paris in coordinated attacks on cafes, bars, a music hall and the Stade de France soccer stadium.

Three suicide bombers sought to enter the stadium but were thwarted by security. The first bomber detonated his vest at a security perimeter, while two other suicide bombers blew themselves up outside the stadium.

Soccer stadiums are a key target for ISIS. In March, the terrorist group claimed credit for bombing a soccer stadium outside Baghdad. A suicide bomber blew himself up, killing 29 and wounding 60.

Both ISIS and al-Qaida have directed operatives to attack sports stadiums inside the U.S., as well.

In 2014, for example, al-Qaida encouraged jihadists to detonate a car bomb at the U.S. Open tennis tournament in Queens, New York.

The popular event was mentioned in an issue of “Inspire,” the al-Qaida-published webzine.

Specifically, operatives were told to attack tennis stadiums, which are “visited by thousands of people, and high-profile people, especially the U.S. Open.”

The NYPD typically floods the tournament with both uniformed and plainclothed officers. But fans will likely to see a larger security presence this year.

The U.S. Open starts on Aug. 29 and ends with the men’s final on Sept. 11 — the 15th anniversary of the Sept. 11, 2001, attacks in New York.