BERLIN (Reuters) - Germany views events in Iran following its presidential election with great concern and has summoned the Iranian ambassador to explain, Foreign Minister Frank-Walter Steinmeier said on Sunday.

He also condemned what he called “brutal actions” against demonstrators in Tehran which he said were unacceptable.

Thousands of people protested on Saturday after President Mahmoud Ahmadinejad won victory in an election that his reformist challenger dismissed as a charade.

“All in all, these are circumstances which have today given me cause to issue the order for the Iranian ambassador to be summoned to the Foreign Ministry,” Steinmeier told Germany’s ARD television.

“I have today, with some European colleagues, already told Iran to immediately make clear whether the election results announced can be taken seriously or not,” he said.

Germany is one of Iran’s biggest trading partners and has also taken a lead, along with Britain and France, in trying to persuade Tehran to drop a nuclear program which the West suspects is being used to develop nuclear bombs.

“We are looking toward Tehran with great concern at the moment. There are a lot of reports about electoral fraud,” Steinmeier said in a separate interview with Germany’s ZDF television.

“We resolutely condemn the actions against demonstrators. It is unacceptable,” he said. In the ARD interview, he condemned the “brutal actions” being taken by the authorities.