Hamburg Police confirmed 76 officers had been injured in the violence.
Two pilots of the ‘Libelle 2’ police helicopter were blinded by lasers shone at them from the ground.
Another officer was hospitalised with an eye injury after a firework exploded in his face.
Police claimed up to 8,000 extremists, some armed with home-made weapons, are targeting the summit, which is surrounded by a ring of steel.
Donald Trump arrived in Hamburg this afternoon to meet with Angela Merkel for a summit sidelines meeting.
About 20,000 officers are on duty over the weekend protecting 6,500 leaders, officials, journalists and other guests.
Police were investigating whether militants targeted a luxury car showroom in the city on Thursday night.