JERUSALEM—The sudden evacuation of a soccer stadium in Hamburg last week less than an hour before the arrival of German Chancellor Angela Merkel was due to a warning by Israeli intelligence of an imminent terrorist attack, according to the German magazine Stern.

The match between Germany and Holland was called off just 90 minutes before the scheduled kickoff. Chancellor Merkel and several of her ministers learned of the warning as they were preparing to head for the stadium. Their visit had been intended to demonstrate the government’s determination not to bow to terrorism in the wake of the attacks in Paris by Islamic State.

Federal Interior Minister Thomas de Maiziere, who took responsibility for calling off the game, said he could give few details because of the need to protect sources and because "some of the answers would upset the population."

Officials in Paris and Brussels have spoken in recent days of the possibility that terrorists were planning to use chemical weapons.

According to Stern, Israel had passed on an initial warning to Germany the day before the scheduled game of an attack in the works, but with few details.

On the day of the match, the information became more concrete, including the target and the hour of the attack, according to Stern.

Hanover Police Chief Volker Kluwe, announcing the cancellation of the game on German TV, said "We had concrete evidence that someone wanted to set off an explosive device in the stadium".

Reports in the German media that a bomb was found in an ambulance near the stadium and that a suspicious package was found on a train have not been confirmed by German security officials.

=If the Stern report of an Israeli intelligence warning is verified, it would seem that Israeli military intelligence or the Mossad have been able to penetrate Islamic State’s operational arm even though there has yet been no direct clash, as far as is known, between Israel and the extremist group in Syria.

There have been clashes with a Jihadi group in Egypt’s Sinai Peninsula, which has affiliated itself with Islamic State and has fired rockets toward the Israeli resort of Eilat. They have also crossed the border into Israel on at least two occasions. Here too, it was Israeli intelligence, which was reportedly the first to declare that a bomb had been placed aboard a Russian airliner bringing tourists back from the resort of Sharm el-Sheikh last month.

It was previously presumed that mechanical problems were to blame. The alleged Israeli report was said to have been based on intercepts of radio transmissions between Jihadi groups in Sinai.

Israeli Defense Minister Moshe Ya’alon told reporters earlier this month that Israel is monitoring the Islamic State and has succeeded in deterring it from attacking the Golan Heights, which borders Syria. He did not elaborate.