Protesters demonstrate against Transatlantic Trade and Investment Partnership (TTIP) free trade agreement ahead of US President Barack Obama's visit in Hanover, Germany April 23, 2016. [Photo/Agencies]

BEIJING - US President Barack Obama is defending his transatlantic trade deal on a visit to Germany though tens of thousands of Germans took to the street to oppose the bill.

In a joint press conference in the northern German city of Hanover, Obama said it is "indisputable" that the Transatlantic Trade and Investment Partnership (TTIP) will make both the EU and US economy stronger and more competitive compared to other regions of the world.

"The United States and the European Union need to keep moving forward with the TTIP," he said after holding talks with German Chancellor Angela Merkel in his final visit to Germany as the US president.

During the trip, Obama opened an industrial technology fair and held talks with Merkel and other European leaders.

However, Obama's trip, which was intended to lend momentum to flagging efforts to see the world's biggest trade pact finalized this year, was embarrassed by the march and rally outside Hanover's opera house.

A loose coalition of trade unions, environmentalists and consumer protection groups said they drew a crowd of 90,000 to take part in the demonstration. Police mobilized a large force to keep order and put attendance at 35,000.

Organizers handed out flags saying "Yes we can - stop TTIP," referring to a slogan used during Obama's election campaign.