Nord Stream: Dramatic footage shows boiling seas after pipeline 'sabotaged'

Watch: Footage by Danish military shows 'boiling' water in Baltic Sea after Nord Stream gas pipeline leaks

Footage showing bubbles rushing to the ocean's surface has been released by Denmark following "unprecedented" leaks from two Russian gas pipelines.

The incident has sparked widespread condemnation among European leaders, who have said the pipes were deliberately sabotaged.

Two mysterious leaks were detected earlier this week at the Nord Stream 1 pipeline - which stopped delivering gas to Europe last month - northeast of the Danish island of Bornholm.

A third has also been detected at the newer Nord Stream 2 pipeline, which is filled with gas but was pulled from commercial operations by Germany in February days before Russia sent troops into Ukraine.

Danish authorities said the largest leak has caused a disturbance of well over 1 kilometre in diameter on the water's surface.

Analysts say such leaks are very rare and operator Nord Stream AG has described the current incident, detected on Monday, as "unprecedented".

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Ships have been urged to stay clear of the site as the bubbling water could mean they lose buoyancy. (Getty Images)

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While it could be down to technical malfunctions or a lack of maintenance, Western leaders have pointed to foul play.

Polish prime minister Mateusz Morawiecki said: "We don't know all the details of what happened, but we see clearly that it's an act of sabotage related to the next step of escalation of the situation in Ukraine."

“Based on the information we have seen so far, much indicates acts of sabotage,” said Norweigan oil and energy minister Terje Aasland.

Mykhailo Podolyak, aide to Ukrainian president Volodymyr Zelenskyy, accused Russia of a “terrorist attack” against the EU to “destabilise the economic situation in Europe and cause pre-winter panic”.

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European Commission chief Ursula von der Leyen warned of the "strongest possible response" should active European energy infrastructure be attacked.

After speaking to Danish prime minister Mette Frederiksen, she said it was paramount to investigate and get full clarity on the "events and why".

The Kremlin has said it did not rule out sabotage as a reason behind the damage, adding it was an issue affecting the energy security of the "entire continent".

Kristoffer Bottzauw, head of Denmark's Energy Agency, said it could take a week for gas to stop draining out of Nord Stream 2, as ships are warned to keep a five-mile radius from the site to avoid losing buoyancy.

"The sea surface is full of methane, which means there is an increased risk of explosions in the area," he added.