A fourth leak on the Nord Stream pipelines has been reported off southern Sweden, the Swedish coast guard said on Thursday.

“We have leakage at two positions” off Sweden, coast guard spokesperson Mattias Lindholm. There are two more off Denmark, he said.

Two of the leaks are on the Nord Stream 1 pipeline that recently stopped supplying gas, while the other two are on Nord Stream 2 which never started operating.

Although they were not running, both pipelines were filled with gas, which escaped and bubbled to the surface.

The Nord Stream pipelines run through the Baltic to transport gas from Russia to Germany. The Danish and Swedish governments believe that the leaks in their countries were “deliberate actions”.

Before the leaks were reported, explosions were recorded. A first explosion was recorded by seismologists early on Monday southeast of the Danish island of Bornholm.

A second, stronger blast northeast of the island that night was equivalent to a magnitude-2.3 earthquake. Seismic stations in Denmark, Norway, and Finland also registered the explosions.

Some European officials and energy experts have said Russia is likely to blame for any sabotage although others cautioned against pointing fingers until investigators are able to determine what happened.

Speaking on Wednesday before the fourth leak was reported, Swedish Prime Minister Magdalena Andersson said it would have taken a large explosive device to cause the damage.