Twenty-thousand cops aren’t enough to stop violent protests at the G20 summit.

Hamburg police called for reinforcement Friday as the city of Altona continues to be ravaged by violent rallies outside the meeting of world leaders.

Currently, there are 20,000 officers on the ground – backed by helicopters, water cannon trucks and surveillance drones — for the two-day summit, including officers from other German states and Austria.

But the special request was made “in order to get relief” amid the tumultuous clashes, according to a police spokesman.

Hamburg police tweeted that their helicopter was nearly hit by a flare Friday morning, according to The Local.

Tens of thousands of anarchists tore through the area overnight Thursday as part of their promised “Welcome to Hell” rally.

So far, 159 police officers have been injured and 45 people have been arrested.

Videos posted on social media show protesters dressed in all black smashing through windows of stores and throwing smoke bombs in the streets.

With Post Wires