Nato threatened a "united and determined response" if the recent damage to the Balticconnector gas pipeline between Estonia and Finland was found to be a deliberate attack.

Nato Secretary-General Jens Stoltenberg said on October 13 that if the damage to the Balticconnector was “proven to be an attack on Nato critical infrastructure … it will be met by a united and determined response from Nato”.

Balticconnector's operators have said it will take at least five months to repair the pipeline. It is the only gas pipeline currently operating to Finland since Russia cut off supplies.

The damage to the pipeline has caused many to point the finger at Russia, which has also been accused of damaging the two Nordstream gas pipelines to Germany a year ago. The Nordstream pipelines were put out of action by explosions.

Estonian and Finnish officials have said the damage to the pipeline appears to be mechanical and perhaps deliberate.

Inspection of the damage done to the pipeline after a loss of pressure was detected early on October 8 showed that  the Balticconnector’s concrete protective cover had been broken or torn off, and the pipeline itself was out of position and badly damaged on one side, Commander Jüri Saska of the Estonian navy told ERR public radio.

A Finnish expert, Jukka Savolainen of the 22-member European Centre of Excellence for Countering Hybrid Threats (Hybrid CoE), told the Finnish public broadcaster YLE that “a large ship” could have dragged its anchor over the pipeline, the Guardian reported.

Estonian media and shipping traffic site Marine Traffic have reported that Russian cargo ship SVG Flot spent the last weekend (October 6-8) in the vicinity of the leak of the Balticconnector natural gas pipeline linking Estonia and Finland. 

Risto Lohi of the Finnish national bureau of investigation told a press conference in Helsinki on October 13 that “there is reason to suspect an external force … caused the damage”. The force, he added, “appears to have been mechanical, not an explosion”. Robin Lardot, the agency’s chief, said marks had been found on the seabed at the site . 

Estonia's Minister of Defence Hanno Pevkur (Reform) said on late October 10 that the damage was inflicted deliberately.

Adding to the suspicions, a data cable belonging to Estonian telecommunications company Elisa, some distance from the pipeline, was also damaged at around the same time.

Whereas the normal pipeline gas pressure stood at around 40 atmospheres (atm) before the incident, it rapidly dropped to 6 atm, meaning there could have been a rupture, while the internal pressure of the gas pipe and that of the water on the seabed equalised, which suggested [the rupture point is at] a depth of 60 metres, Estonian and Finnish media reported.

Cdre Saska said that, while it looks just as if this was torn away on one side and the concrete has broken or peeled off, specifically at that rupture point, whether this damage is only at that spot or [the pipeline] has been further damaged due to a lateral force is again something for the investigators to establish and answer.

“It still looks like it was torn from one side, a bit like a hosepipe getting stuck behind your leg, then you've dragged it behind you,” he emphasised, adding that further speculations are premature.

Meanwhile, Russia’s TASS, a Russian state news agency, cites Dmitry Peskov, the Kremlin’s spokesman as saying that “dangerous precedents of terror attacks against critical infrastructure facilities on the Baltic Sea had already been set, meaning certain attacks against Nord Stream pipelines”.

Russia will wait for more detailed information about the incident at the gas pipeline between Finland and Estonia, Peskov said.