Ukraine has denied any involvement in September’s attack on the Nord Stream pipelines, which were built to carry Russian natural gas to Germany.
The denial follows a report from the New York Times, which cites anonymous US intelligence officials who suggest a pro-Ukrainian group was to blame.
Mykhailo Podolyak, an adviser to the Ukrainian president, said Ukraine “was absolutely not involved”.
Moscow questioned how the US could make assumptions without an investigation.
Kremlin spokesman Dmitry Peskov called the report a “co-ordinated fake news media campaign” and told the state news agency Ria-Novosti those who attacked the pipeline “clearly… want to divert attention.”
Russia has blamed the West for the explosions and called on the UN Security Council to independently investigate them.
German investigators said on Wednesday they had searched a ship in January which was suspected of transporting the explosives used to sabotage the two gas pipelines. There was at this stage no evidence to suggest a foreign state was involved, they said.
Russian gas deliveries had been suspended before the blasts. Russia shut down the Nord Stream 1 pipeline in August last year, saying it needed maintenance. Nord Stream 2 had never been put into service.
The exact cause of the 26 September blasts that hit the natural gas pipelines is unknown, but it is widely believed they were attacked.
Nato and Western leaders have stopped short of directly accusing Russia of attacking its own pipelines, although the EU has previously said Russia uses its gas pipelines as a weapon against the West.
- A journey to the site of the Nord Stream explosions
On Tuesday, the New York Times reported that new intelligence reviewed by US officials suggested that a pro-Ukrainian group had carried out the attack on the Nord Stream pipelines.
Citing anonymous US officials, the report said there was no evidence that Ukrainian President Volodymyr Zelensky or his top lieutenants were involved in the operation.
The US newspaper reported that the officials declined to disclose the nature of the intelligence, how it was obtained or “any details of the strength of the evidence it contains”.
It added: “Officials who have reviewed the intelligence said they believed the saboteurs were most likely Ukrainian or Russian nationals, or some combination of the two.”
Responding to the New York Times report, Mr Podolyak added that Kyiv had no information about what had happened.
Meanwhile, German website Die Zeit reported that German authorities had made a breakthrough in their investigation into the cause of the attacks.
According to joint research by several German media organisations, the boat used to plant the explosives was a yacht hired from a firm based in Poland, which reportedly belonged to two Ukrainians. The nationalities of those who carried out the attack were unclear.
German investigators later refused to confirm details of the report but said that a ship had been searched seven weeks ago.
Defence Minister Boris Pistorius warned against jumping to conclusions. It could be a false-flag operation aimed at pinning the blame on pro-Ukrainian groups, he told German radio: “The likelihood of one [theory] or the other is just as high.”
At least 50m (164ft) of the underwater Nord Stream 1 pipeline bringing Russian gas to Germany is thought to have been destroyed by September’s blast.
Danish police believe “powerful explosions” blew four holes in the pipe and its newer twin, Nord Stream 2.
German, Danish and Swedish authorities have all been investigating the incident.
Mr Peskov said Nord Stream shareholder countries should insist on an urgent, transparent investigation.
“We are still not allowed in the investigation,” he said. “Only a few days ago we received notes to that effect from the Danes and Swedes. This whole thing is not just weird. It reeks of a heinous crime.”
For decades, Russia supplied huge amounts of natural gas to Western Europe. But after the war in Ukraine began in February of last year, most EU countries drastically reduced their reliance on Russian energy.
