Estonia is pursuing the same Chinese ship as Finland in its enquiries into the latest mystery to strike Nato’s underwater pipes and cables.

“Further investigation will focus more on the [Chinese] vessel and its activity,” Estonian state prosecutor Triinu Olev told EUobserver on Wednesday (25 October).

“We are working with our [Nato and EU] partners to check all other sites of underwater infrastructure,” Estonia’s foreign minister Margus Tsahkna also said, in a sign of how badly the incident jangled nerves.

The alarm comes after something ripped apart the Balticconnector gas pipeline from Estonia to Finland on 8 October, which stretches for 77km at depths of down to 100 metres.

Something also damaged nearby telecommunications cables from Estonia to Finland and Estonia to Sweden.

The Estonian prosecutor general’s office and the Finnish National Bureau of Investigation (NBI) have formed a joint investigation team.

Estonian and Finnish security services and navies also visited the maritime scene last week, despite stormy conditions.