German police said a bomb threat forced them to call off an international football match Tuesday that was meant as a "symbol of freedom" after the Paris attacks and was to be attended by Chancellor Angela Merkel.
No explosives had been found so far and no arrests made after the Germany-Netherlands football match was cancelled and thousands of fans evacuated, said Lower Saxony state interior minister Boris Pistorius.
Hanover city police chief Volker Kluwe said there had been "serious plans to cause an explosion" in the city's 49,000-capacity stadium, and that authorities had acted on "a concrete threat scenario".
"We received a serious indication that a bomb attack was planned inside the stadium tonight," he told public broadcaster ARD.
The German team was playing France in Paris last Friday when the Stade de France was rocked by three blasts triggered by Islamic extremist suicide bombers outside the venue.
Head coach Joachim Loew had called Tuesday's planned match "a clear message and symbol of freedom and a demonstration of compassion, as well as sorrow, for our French friends - not only in France, but throughout the world".
Before the match, players had been practising the French anthem "La Marseillaise", which they had been set to sing in a sign of solidarity with the shaken neighbouring nation.
"They wanted to make a statement against fear and terrorism, but it wasn't to be," said disappointed fan Philipp Beckermann, 38, from Dortmund, who was heading away from the stadium.
"We didn't even get into the stadium before we heard it was called off," he said, leaving the area with his girlfriend Judith.
"There was no information about why the game was called off, security has to come first I guess. But it's going to be a pretty sad journey back to Dortmund for us now for nothing."
Interior Minister Thomas de Maiziere - who had been due to attend the match, with Merkel - later said the event was cancelled "to protect the population", but did not provide specifics.
He said "we had good reasons, difficult reasons" but added that describing them could "cause concern to the population".
Pistorius told the press conference that rumours of an explosives-packed ambulance could not be confirmed.
Thousands of fans were evacuated from the HDI Arena less than two hours before the game had been due to start, as hundreds of police, some on horseback, secured the area.
The evacuation proceeded smoothly, with no signs of panic.
Merkel had just landed by plane with de Maiziere when the decision to scrap the match was taken, and the chancellor flew back to Berlin, the minister said.
The German team's bus, with the logo "Die Mannschaft" on its side, could be seen driving away, guarded by a convoy of police cars, in a fan's video clip published online by top-selling Bild daily.
"They are safe," German Football Association (DFB) interim president Rainer Koch told sports news agency SID, an AFP subsidiary.
Police told the crowd on megaphones: "Ladies and gentlemen, dear football fans. We're sorry, but the match has been cancelled at short notice. Please stay calm, there is no imminent danger. Just please simply go home."
Police also advised people to avoid public transport and were checking cars, leading to lengthy traffic jams bathed in the blue light of flashing police sirens.
The victims of the Paris attacks - which claimed 129 lives with more than 350 injured - had been set to be honoured by candlelight in what had been billed as "a friendly in the true sense of the word".
The DFB had at the weekend already come close to calling off the match, while Belgium cancelled their friendly against Spain on Tuesday.
The German team are still coming to terms with what they experienced last Friday.
After the blasts, the Germans spent the night in the Stade de France changing room, as it was considered too dangerous for them to cross Paris. They flew home early the next morning.
"There was a lot of fear and anxiety in the dressing room that night," said Loew. "We were afraid."