Multiple countries are investigating and the authorities in Europe say they have not ruled out sabotage. But U.S. intelligence officials have assessed that the cables were not cut deliberately.

Sweden's prime minister says his government has formally asked China to cooperate in explaining the recent rupture of data cables on the Baltic Sea bed in an area where a China-flagged vessel was sighted.

Sweden asked for Beijing's cooperation with an investigation.China said on Friday it was ready to assist in a probe into the severing of two cables in the Baltic Sea. It comes after Sweden asked for Beijing's cooperation in the probe into the rupture of two data cables on November 17-18 in an area where a China- flagged vessel had been sighted.