German police have arrested a man suspected of having purchased equipment for Iran's ballistic missile program in breach of international sanctions, prosecutors said Wednesday.

The suspect detained Tuesday was identified only as German-Iranian dual national Ali Reza B., 62, who had lived in or around Bonn, western Germany, they said.

Anti-government protesters were locked in a stand-off with riot police across burning barricades Wednesday after fierce clashes left at least 26 people dead in Ukraine's worst crisis since the collapse of the Soviet Union.

The crackdown by security forces triggered a storm of international condemnation, with the White House calling the violence "completely outrageous".

EU foreign policy chief Catherine Ashton on Tuesday denounced the "grave new escalation" in Kiev, where at least five people were killed and scores hurt as protestors battled police.

"I am deeply worried about the grave new escalation in Kiev and the reported victims," Ashton said in a statement, saying she condemned "all use of violence, including against public or party buildings."

Ukrainian opposition protesters on Tuesday attacked the party headquarters of embattled President Viktor Yanukovych as fierce clashes with police erupted again in Kiev for the first time in weeks.

Protesters briefly seized the party headquarters after several hundred attacked it with Molotov cocktails and smashed their way inside but later withdrew as smoke continued to billow from part of the building, an Agence France Presse reporter at the scene said.

A German court on Tuesday sentenced a former Rwandan town mayor to 14 years in jail for aiding genocide in a church massacre of hundreds of people 20 years ago.

The defendant, Onesphore Rwabukombe, 56, the former mayor of the town of Muvumba in northeastern Rwanda, showed no visible reaction when he was found guilty.

German Chancellor Angela Merkel welcomed Monday a political amnesty in Ukraine as a "positive step" but urged progress now on a new government, after talks with pro-EU opposition leaders, her spokesman said.

Merkel stressed that Germany and the EU would do everything to contribute towards a "positive outcome" to the country's worst post-Soviet crisis, spokesman Steffen Seibert said in a statement.

Iran's ambassador to Moscow on Monday said Russia could build the Islamic republic a second nuclear power reactor in exchange for massive oil shipments that have raised grave concern in Washington.

Ambassador Mehdi Sanaei said the two close trading partners have been negotiating Iran's delivery of hundreds of thousands of barrels of oil a day since a meeting at a regional summit in September between Russian President Vladimir Putin and his counterpart Hassan Rouhani.

Germany plans to beef up its counterintelligence tactics against allied countries in response to revelations of widespread U.S. spying, Der Spiegel magazine reported Sunday.

The weekly said the German government was considering deploying its own agents to keep tabs on Western secret services and embassies on German soil including those of the United States and also Britain.

China's "Black Coal, Thin Ice" by Diao Yinan about a washed up ex-cop investigating a series of grisly murders won the Berlin film festival's Golden Bear top prize Saturday.

The classic film noir, whose Chinese title is Bai Ri Yan Huo, also captured the Silver Bear best actor award for its star Liao Fan.

Chancellor Angela Merkel said Saturday that Germany wanted to bolster its military cooperation with France, particularly in war-torn areas of Africa, ahead of a joint cabinet meeting next week.

"I agreed with French President Francois Hollande that we wanted to use the Franco-German meeting to discuss new projects ... especially in the area of security and particularly in Africa," Merkel said in her weekly podcast.