KYIV-Ukraine has accused Russia of causing leaks in two major gas pipelines to Europe in what it described as a “terrorist attack”.

Ukrainian presidential adviser Mykhaylo Podolyak said the damage to Nord Stream 1 and 2 was “an act of aggression” towards the EU.

He added that Russia wanted to cause pre-winter panic and urged the EU to increase military support for Ukraine.

Seismologists reported underwater blasts before the leaks emerged.

“There is no doubt that these were explosions,” said Bjorn Lund of Sweden’s National Seismology Centre, as quoted by local media.

The operators of Nord Stream 2 warned of a loss of pressure in the pipeline on Monday afternoon. That led to a warning from Danish authorities that ships should avoid the area near the island of Bornholm.

The operator of Nord Stream 1 said the undersea lines had simultaneously sustained “unprecedented” damage in one day.

Denmark’s Defence Command has released footage of the leaks which shows bubbles at the surface of the Baltic Sea near the island.

The largest patch of sea disturbance is 1km (0.6 miles) in diameter, it says.

“Gas leak from NS-1 [Nord Stream 1] is nothing more than a terrorist attack planned by Russia and an act of aggression towards the EU. Russia wants to destabilise the economic situation in Europe and cause pre-winter panic,” Ukraine’s Mr Podolyak tweeted in English.

He also called on European partners, particularly Germany, to increase military support for Ukraine.