Groundless allegations US astronauts might be responsible for causing damage to the Russian spacecraft Soyuz MS-09, attached to the ISS, are extremely dangerous and absolutely unacceptable, Russia’s Deputy Prime Minister Yuri Borisov said in the wake of media publications on that score.

"It is absolutely impermissible to cast a shadow either on our cosmonauts or US astronauts," he said.

"A probe is underway. As long as the investigation continues, it will be utterly wrong to pronounce any such verdicts. The final results are to be obtained first to find out the origin of the hole. It should not be ruled out that faulty workmanship is to blame," Borisov said.

"It remains a hard fact that the drop in air pressure occurred after the spacecraft has been in space for several months. The hole is very small. It is very good it was promptly identified and the necessary measures taken," Borisov said.

He pointed out that the International Space Station "is an integral team where there are no political disagreements and cannot be any."

"The investigation is still on. Labelling and witch-hunt will be short-sighted and risky, to say the least," he concluded.

The daily Kommersant on Tuesday quoted its sources as saying that the Roscosmos probe was considering, among other likely causes of the damage to Soyuz, deliberate actions by US astronauts, who in this way wished to speed up their return home. According to the newspaper, the astronauts might have drilled the hole because one of the crew members was unwell. Urgent evacuation of all crewmembers would allow for getting full treatment, while the compartment where the hole was found would have burned down in the atmosphere. Roscosmos said it would refrain from comment until the special probe reported its findings.