"Welcome to Hell". That's the greeting for U.S. President Donald Trump and other world leaders from anti-capitalist protesters in Hamburg who aim to disrupt the G20 summit, already rife with tensions over trade and climate change.
Thousands of protesters from around Europe were pouring into the port city to join big demonstrations later. Police expected around 100,000 protesters in Hamburg, some 8,000 of whom are deemed by security forces to be ready to commit violence.
This poses a challenge for those tasked with securing the July 7-8 summit of leaders of the world's 20 biggest economies, hosted by Chancellor Angela Merkel, who face tough talks on divisive issues including trade and climate change.
On the sidelines of the summit, Merkel will meet leaders including Turkey's Tayyip Erdogan and Trump, who in Poland called again on NATO partners to spend more on defence and said he would confront the threat from North Korea.