LONDON (AA) – Thousands of protesters marched in the German city of Hannover against the Transatlantic Trade and Investment Partnership (TTIP) – a free trade deal being negotiated between the U.S. and the European Union.

The rally that attracted 90,000 people according to organizers – 30,000 according to police – was staged on Saturday, a day before U.S. President Barack Obama’s visit to the city where he will meet German Chancellor Angela Merkel.

Obama is expected to promote the TTIP agreement when he joins Merkel to open the world’s largest industrial trade fair in the northern German city of Hanover on Sunday.

Critics argue the TTIP would drive down wages, erode consumer protection and environmental standards. Courts, opponents of the pact maintain, could place the interests of corporations above those of democratically elected governments, citing a recent case where tobacco giant Philip Morris sued Uruguay over a law requiring graphic warnings on cigarette packages.

The 13th round of TTIP talks is set to start on Monday in New York. The talks have come under heavy criticism for the secretive manner in which they have been conducted.

US lawmakers have only been permitted to view the draft documents in special reading rooms and are forbidden from talking about the documents with experts, the media or their constituents.

On the other side of the Atlantic, Germany’s chancellor has been forced to defend the secrecy in negotiations on the free trade agreement between the EU-bloc and the US.

It cannot “always be accessible to everyone in advance,” Merkel said in her weekly podcast published on Saturday.

“Protect Democracy, Stop TTIP,” the protesters shouted in a rally that attracted trade unions, environmentalist organizations, non-governmental organizations and opposition party members.

A giant poster hung on a central building by Greenpeace read “Yes we can stop the TTIP”.

CETA (Canada-EU Comprehensive economic and Trade Agreement) was also protested.

Currently in London, U.S. President Obama will Merkel Sunday at the historic Herrenhausen Palace for further negotiations over the TTIP.

*Ayhan Simsek contributed to this story from Hannover.

Additional reporting from dw.com

Author Ahmet Gürhan Kartal

[Photo: Protesters attend a protest against the TTIP and CETA free trade agreements march on the eve of a visit by U.S. President Barack Obama on April 23, 2016 in Hannover, Germany. Photograph: Mehmet Kaman/AA]