Such an action at this depth and on this scale could be carried out "only by specialists," Putin said in a television interview broadcast on Tuesday.
"This also still requires the support of a state that has the appropriate technology."
Putin did not want to comment specifically on who may have triggered the explosions that knocked out three of the four strands of the natural gas pipelines.
But one must always question who might have an interest in this, he added.
"And who is interested? Theoretically, the US could have an interest in preventing Russian energy carriers from entering the European market," Putin said.
According to the president, a Gazprom ship had also discovered evidence of the presence of another device on the gas pipeline 30km from one of the explosion sites.
Something was detected at the pipe junction that experts believed "could be an antenna to receive a signal to detonate an explosive device," he said.
Explosions occurred on September 26 on the Nord Stream 1 and 2 pipelines lying at the bottom of the Baltic Sea.
Germany, Sweden and Denmark have launched investigations but so far not identified the perpetrators.
Last week, media in Germany and the US reported clues to the possible course of events.
According to these, a group of six people with forged passports rented a yacht and planted the explosives unnoticed in 80 metres of water.
The media had speculated about the involvement of a pro-Ukrainian group.
Ukrainian President Volodymyr Zelenskiy rejected the claims of Ukrainian involvement as "ridiculous".
