US President Donald Trump praises German Chancellor Angela Merkel for the way she handled the G20 summit, which highlighted isolation of the US from every other major economy on issues such as climate change and protectionism.
The twelfth meeting of the Group of Twenty was held at Hamburg Messe, in the city of Hamburg, on Friday and Saturday.
"The G20 Summit was a wonderful success and carried out beautifully by Chancellor Angela Merkel. Thank you!" Trump said in a tweet on Saturday.
Nighttime riots broke out in the Schanzenviertel area on Friday, which went uncontrolled for a period of three hours. The protesters had previously started their campaign against the summit, which brought world leaders together for the annual event.
Similar protests prevented First Lady Melania Trump from leaving her residence in Hamburg.
"Law enforcement [and] military did a spectacular job in Hamburg. Everybody felt totally safe despite the anarchists," Trump tweeted.
Some 20 German police officers are said to have sustained injuries.
According to the White House, Merkel and Trump spoke on “a range of shared foreign and security policy priorities” during their meeting outside of the summit.
Trump also met with leaders of other key states such as Russian President Vladimir Putin.
Putin said later that Trump "asked a lot of questions" on the issue of Russia's alleged role in the US 2016 presidential election, which is currently under congressional and FBI investigation in the US.