German police said on Friday several people, including one cash transport driver, had been taken hostage at a savings bank branch in the western town of Sinzig.
"It is currently believed that there are several perpetrators and hostages inside the bank," police said in a statement, adding that the situation was currently "stable".
Police also said they had launched extensive operations and had cordoned off a large area.
The incident was reported in the town's centre in the regional state of Rhineland-Palatinate at 0700 GMT, police added.
There is no danger to the public outside the cordoned-off area, according to the police.
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