A Russian vessel is suspected of a territorial violation of Finland’s marine area in the Gulf of Finland, an arm of the Baltic Sea, the Finnish defense ministry said on Friday.

The suspected violation, which the Finnish Border Guard is currently investigating, took place in the eastern part of the Gulf of Finland Friday afternoon, a brief government statement said.

The ministry didn’t disclose further details of the incident but the Finnish newspaper Helsingin Sanomat said, citing information from border officials, that the suspected vessel is the Russian Navy’s hydrographic survey ship, the Mikhail Kazansky.

The Russian vessel, used among other things for underwater topography and repair work, entered into Finnish territorial waters south of the town of Hamina without authorization just after noon Friday, and the violation lasted about seven minutes, the newspaper said.