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MAINZ, Germany — Two home-made bombs hit a mosque and a conference center in eastern Germany late Monday in what officials called a "xenophobic" and "cowardly" attack.

No one was injured by the blasts in Dresden, birthplace of a German grassroots anti-Islam movement known as PEGIDA.

The city's police chief said officials were "now in crisis mode."

The entrance to the Fatih Camii Mosque in Dresden, seen after the attack. SEBASTIAN KAHNERT / AFP - Getty Images

Police said the first bomb exploded outside a mosque in the western part of the city at around 10 p.m. local time [4 p.m. ET] while the imam, his wife and two sons were inside.

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Around 30 minutes later, another explosion struck outside the city's International Congress Center. The large, modern building on the banks of the Elbe River is hosting events this weekend for the annual Day of German Unity, which celebrates the country's 1990 reunification after the fall of the Berlin Wall.

Investigators said they found parts of home-made bombs at both locations but have declined to comment on whether they have any suspects.

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"Even though there has been no claim of responsibility, we have to assume that there is a xenophobic motive," Dresden police chief Horst Kretzschmar said in a statement.

Police also believe there is "a connection" between the explosion at the conference center and the Day of German Unity celebrations being held there.

"This is a cowardly attack," Saxony Interior Minister Markus Ulbig told a press conference Tuesday. "It is the duty of police to do everything to quickly identify the perpetrator or the perpetrators and bring them to justice."

Dresden, Germany. Google Maps

Police officers have been sent to protect five Islamic centers including three mosques in the city, and the explosions "will have an effect on the ongoing security preparations" for the weekend, Kretzschmar said.

He added: "We are now in a crisis mode."

Dresden was the birthplace in 2014 of the anti-Islam PEGIDA movement, whose name is an acronym for Patriotic Europeans Against the Islamisation of the West.

The group has seized upon an influx of refugees and migrants into Germany and has held several rallies of thousands of people across the country.

Last week, a government report warned that xenophobia was rising in ex-communist eastern Germany.