COPENHAGEN - Sweden's Armed Forces said on Wednesday they were back at the site of the Russian Nord Stream gas pipeline leaks in the southern part of the Baltic Sea to further investigate the suspected blasts.

World leaders have called the damage to the pipes, discovered last month in Danish and Swedish economic zones, an act of sabotage, without saying who could be responsible.

Swedish prosecutors and police earlier this month wrapped up a crime scene investigation with the help of the Navy and Coast Guard. Both Sweden and Denmark have concluded that the four leaks were caused by explosions.

"The Swedish Armed Forces are this week carrying out complementary seabed surveys at the gas leaks with minesweepers," the armed forces said on Twitter on Wednesday.

"The investigation is done at our own initiative and is not part of the police investigation."

A navy spokesperson said the new survey was expected to be completed this week.

"This is truly out of national military interest," he said. "I can't comment on what we are looking for, why we are there, but we had the need to come back to do an additional search."

Dwindling flows of gas from Russia, which once supplied 40% of Europe's needs, has left the European Union struggling to unite over how to respond to surging prices that have deepened a cost-of-living crisis for families and businesses.

(Reporting by Stine Jacobsen and Anna Ringstrom, editing by Terje Solsvik and Nick Macfie)