FILE PHOTO: Norbert Roettgen walks at the fraction level of the German lower house of parliament Bundestag in Berlin, Germany June 14, 2018. REUTERS/Michele Tantussi

BERLIN (Reuters) - Europe may need to impose tougher sanctions against Moscow following Russia’s seizure of Ukrainian vessels, an ally of German Chancellor Angela Merkel said on Tuesday.

Ukraine President Petro Poroshenko has warned of the “extremely serious” threat of a land invasion after Russia seized three Ukrainian naval ships and took their crew prisoner at the weekend.

Norbert Roettgen, a member of Chancellor Angela Merkel’s Christian Democratic Union who chairs the German parliamentary foreign affairs committee, said Russia’s behavior was deeply worrying and that tougher sanctions were an option.

“So far there are no talks about tougher sanctions but I generally would not rule this out,” Roettgen told Deutschlandfunk radio.

“In my view, such behavior cannot remain without consequences and I don’t think one should say that there won’t be any further sanctions.”

Merkel has stressed the need for dialogue while the European Union, Britain, France, Poland, Denmark, and Canada all condemned what they called Russian aggression.