A pair of warships from the Iran Navy were spotted sailing through the Baltic Sea on Thursday on their way to St. Petersburg, Russia, for a naval parade taking place later this month, United Press International (UPI) reported.

Satellite imagery marked the ships before they entered the English Channel, The Drive reported, which includes the sea-base ship Makran and the frigate Sahand, Iran's most modern warship.

They were off the coast of Senegal before crossing the Bay of Biscay and the English Channel, eventually crossing into the Baltic Sea. The Danish military has been following the vessels through the sea,  the Danish Defense Ministry said on Thursday.

Makran passed the Great Belt Bridge around 7 a.m. local time with a Fast Attack Craft on its deck. Sahand entered the Baltic Sea from a different route, according to USNI News.

Iranian officials notified authorities in Copenhagen that the ships would be transiting through Danish waters to Russia, the Guardian reported.

The ships are expected to represent the Iranian Navy in a parade celebrating the 325th anniversary of the Russian Navy.

U.S. officials worried that the ships would head toward Venezuela when they entered the Atlantic Ocean before turning toward the English Channel.