Story highlights No one was injured in attacks on mosque and International Congress Center

Police: Attacks happened at the same time, suggesting they're related

(CNN) Security has been stepped up in the German city of Dresden, following two bomb attacks on a mosque and a conference center Monday evening.

No one was injured in the attacks, which included two homemade devices, according to police.

The bombings come ahead of next weekend's German Unity Day celebrations, which German Chancellor Angela Merkel is expected to attend. The celebrations mark the 26th anniversary of the reunification of East and West Germany.

Dresden's International Congress Center is cordoned off Tuesday after a bomb attack.

The explosions -- first at the mosque and then at the International Congress Center -- happened within minutes of each other, leading police to believe they're related.

Part of Dresden's Unity Day celebrations were set to be held at the center.

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