US President Barack Obama arrived in Hanover on Sunday for the start of his last visit to Germany before he leaves the White House in January.
The premier of the northern German state of Lower Saxony, Stephan Weil, welcomed Obama before the president headed off for talks with German Chancellor Angela Merkel on global and security issues.
Obama and Merkel will then officially open the annual Hannover Messe, the world's biggest industrial trade fair. The US will be fair's partner nation for the first time.
Obama's two-day trip to Hanover, which his fifth and likely his last visit to Germany, represents the last leg of a three-nation trip, which forms part of Obama's farewell to world leaders.
The president and Merkel are expected to use his visit to try to give fresh momentum to a controversial US-European Union trade deal, aimed at creating the world's largest free trade area with 800 million people.
The 13th round of the Transatlantic Trade and Investment Partnership (TTIP) talks is due to take place in New York next week.
Negotiators on both sides of the Atlantic have expressed hope in concluding the talks under the Obama administration, but time is running short with US elections due in November.
A survey by pollsters Emnid conducted for the news channel N24 and released on Friday found that 84 per cent of German respondents were satisfied with Obama's eight years in the White House. Only 7 per cent were unhappy with his period in office.
But there was anger on the streets of Hanover on Saturday, when tens of thousands of people rallied against TTIP with protesters arguing it will undermine workers' rights, boost the power of big corporations and weaken food and other standards.
Sunday's talks between Merkel and Obama come ahead of the July NATO summit in Warsaw and are expected to focus on terrorist threats and international flashpoints such a Syria and Libya, building on themes that emerged during his meeting with British Prime Minister David Cameron in London last week.
The German news magazine Der Spiegel also reported that Obama will call on Merkel to agree to deploy more German troops on NATO's eastern border as part of efforts to help contain a more aggressive Russia.
Large parts of Hanover – a city of more than 500,000 residents – have been turned into a special security zone during the president's visit.
Hanover residents have been told by officials that for security reasons they should keep away from their windows and refrain from waving at Obama when his motorcade passes through the city, which is the capital of northern Germany state of Lower Saxony.
Police said they have warned about 1,800 residents living on the route the president will take to the trade fair grounds not to trigger a check of their apartments or buildings by standing too close the windows.
The president is set to attend a special dinner on Sunday attended by business and political leaders, which Merkel is hosting at Hanover's Herrenhausen castle, whose history and vast baroque gardens date back to the 17th century.
After joining Merkel for the traditional tour of the fair on Monday morning and a speech to business leaders, Obama and the chancellor will attend a mini summit also comprising the leaders of France, Italy and Britain.
Obama's meeting with Merkel as well French President Francois Hollande, Italian Prime Minister Matteo Renzi and British Prime Minister David Cameron also will key focus on international issues.
In particular, the talks will also include the fight against Islamic State in Iraq and Syria, the European refugee crisis and Libya, the White House said.