STOCKHOLM (AP) — A fourth leak on the Nord Stream pipelines has been reported off southern Sweden, the Swedish news agency said Thursday.

Sweden’s coast guards told news agency TT that they have a vessel on the site of the leak, off Sweden. All four detected leaks are in international waters, two near Sweden and two near Denmark.

The Nord Stream pipelines run through the Baltic to transport gas from Russia to Germany. Neither pipeline was operating, but both were filled with gas. The Danish and Swedish governments believe that the leaks off their countries were “deliberate actions.”

Before the leaks were reported, explosions were recorded. A first explosion was recorded by seismologists early 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 — it directly benefits from higher energy prices and economic anxiety across Europe — although others cautioned against pointing fingers until investigators are able to determine what happened.