By Christina Amann and Ilona Wissenbach

BERLIN (Reuters) -A shooting at a Mercedes-Benz plant in southwestern Germany left two men dead on Thursday, and police have detained a suspect, mounting pressure on Berlin to tighten the country's already-strict gun laws.

The suspect, 53, opened fire on the victims before security workers at the site in the southern German city of Sindelfingen held him down and handed him over to police, police and the local prosecutor's office said in a statement.

The suspect did not resist arrest, they said, and the victims, both aged 44, died of their injuries.

The incident was the latest of a number of mass shootings in Germany in recent years, many of which had a connection with extremism. Investigators have yet to establish a motive for Thursday's shooting.

The German government had vowed to tighten its gun laws further after a gunman opened fire on people gathered in a Jehovah's Witnesses hall in Hamburg in March, killing six.

Interior Minister Nancy Faeser had said after that attack that the government would revisit its arms laws. The Social Democrats, her party and that of Chancellor Olaf Scholz, have been pushing for tougher restrictions, and Germany's police union also called for a swift legislative response to restrict the number of guns available.

Mercedes-Benz produces its flagship S-Class luxury sedan at the Sindelfingen plant, located some 17 km (10.6 miles) southwest of Stuttgart.

The company said the gunman and the two victims belonged to an external services provider.

"We are deeply shocked and saddened by the tragic news," Mercedes said in a statement, adding that there was no longer any danger to the local population or workers at the plant.

The production site - with a workforce of 35,000 - was evacuated following the shooting, which took place after the suspect entered the site at 7:45 a.m. (0545 GMT), police and the Stuttgart prosecutor said.

Germany outlawed certain large magazines in 2020 and conducts five-yearly checks on gun owners to ascertain whether their possession of a weapon is justified.

In 2012, a shooting at a factory site for technology firm 3M in the western German town of Hilden left one dead and four injured.

(Reporting by Christina Amann, Rachel More, Ilona Wissenbach and Miranda Murray; writing by Matthias Williams and Rachel More; editing by Friederike Heine and Bernadette Baum)