Dozens of police and demonstrators were injured as protests turned violent the day before a Group of 20 (G20) summit in Hamburg on July 6, while among world leaders tensions over trade and climate change remained unresolved.
Police clashed with anticapitalist demonstrators near the summit venue, firing water cannons and using pepper spray against hundreds of black-clad protesters after they threw bottles.
Nearly 75 police officers were injured during the evening, with three requiring treatment in hospitals, police said. The pilots of a police helicopter sustained eye injuries when laser pointers were directed at them, police said.
Many protesters also were injured in the clashes, even as some of the demonstrators wreaked havoc, roving the streets throwing bottles, smashing windows, and setting cars and other objects on fire.
About 13,000 protesters took to the streets on July 6, including about 1,000 masked anarchists. Police expect as many as 100,000 protesters to descend on the port city during the weekend summit. Germany has deployed some 20,000 police to provide security.
Tensions simmered among world leaders ahead of the summit as well, as German Chancellor Angela Merkel struggled to reach agreement on the wording of a communique to be issued by the leaders of the 20 largest economies addressing everything from terrorism and trade to climate change and migration.
After a meeting between Merkel and U.S. President Donald Trump, German Foreign Minister Sigmar Gabriel said "clear differences" on climate change and trade continued to divide the two allies, though they also found "many commonalities."
About 13,000 protesters took to the streets of Hamburg on July 6, accompanied by thousands of riot police.
"The question is whether the Americans remain convinced that the only thing that counts on global trade is whether America is the winner or not," Gabriel told public broadcaster ARD.
"Or can we manage to convince the Americans that if everyone plays by the same rules, then this will be best for everyone," he said.
The G20 leaders used to routinely issue pledges to fight protectionism, but Trump's "America First" trade policy has blocked a consensus among world leaders on globalization and trade since he took office.
The group appeared unlikely to be able to reach a consensus on climate change, as well, because of Trump's withdrawal from the 2015 Paris climate agreement, which all the other leaders signed, Merkel said.
"Many many other countries want to go on implementing" the pact, she said, and some nations are calling for measures to accelerate the fight against global warming.
"We are not going to paper over the differences, but rather we will call discord discord," she said.
Merkel and Trump also discussed at their meeting North Korea, the Middle East, and the conflict in eastern Ukraine, German and U.S. officials said, without providing details.
Gabriel and U.S. Secretary of State Rex Tillerson were present at the meeting.
Trump also on July 6 attended a dinner with South Korean President Moon Jae-in and Japanese Prime Minister Shinzo Abe where they discussed North Korea's intercontinental ballistic-missile test earlier this week.
On the first day of the summit on July 7, Trump is scheduled to meet in the morning with Mexican President Peña Nieto before a working lunch with other leaders.
Pena also said that Mexico would work to make sure that the G20 adopts "neither protectionist measures nor backsliding on the liberalization of global trade, since these have proven again and again to have detrimental outcomes for everyone."
"No country on its own -- no matter how big, powerful, or influential as it may be -- can make progress without others," he said ahead of his meeting with Trump.
Trump's much-anticipated meeting with Russian President Vladimir Putin will occur in the afternoon after the first working session of the summit, the White House said.