Divers working on the wreck of the Kursk have begun piercing the last of 26 holes in the vessel's hull.
A barge carrying equipment for the next phase of the salvage effort is nearing the disaster site.
The international team has been cutting holes in the hull that will be used to attach steel cables to the vessel to hoist it to the surface.
Meanwhile, the Carrier barge, bearing equipment needed to separate the submarine's first compartment from the rest of the vessel, is making its way from the Norwegian port of Kirkenes.
It is expected to arrive at the site in the Barents Sea tomorrow, Russian Navy spokesman Igor Dygalo says.
The first compartment - which was mangled by the explosion that sank the Kursk last August, killing all 118 men on board - will be left behind when the Kursk is raised.
Russian officials say it is too dangerous to lift because it could contain unexploded torpedoes.
Once the Carrier arrives, the preparation for severing the fore section is expected to take seven or eight days and the actual cutting should take two days, Vyacheslav Zakharov, a spokesman for the Dutch company Mammoet, said.
Mammoet is heading the salvage operation.
Mr Zakharov says the navy has ruled out the possibility of an explosion in the first compartment during the cutting phase.
"We are not expecting an explosion," he said. "But, nevertheless, the architects of the project maintain that even if there is an explosion, the consequences won't be catastrophic."
Foul weather has caused delays in the operation recently, but officials maintain they are sticking to the original schedule.
According to the timetable, the Kursk should be lifted to the surface on September 15 and then towed to harbour.