President Vladimir Putin's spokesman said plans for a new submarine-launched nuclear torpedo shown on Kremlin-controlled television were secret and should never have been aired.

NTV and Channel One showed a large document — filmed over a military officer's shoulder during a meeting with Putin — with drawings and details of a weapons system called Status-6.

The torpedoes could create "extensive zones of radioactive contamination" that would make enemy coastal areas "unsuitable for military, economic, business or other activity for a long time," the document said.

The channels later removed the footage, which was shot during a meeting on Monday in Sochi.

"It's true that some secret information was caught by the camera and therefore it was subsequently removed," Putin spokesman Dmitry Peskov said late Wednesday. "We hope this will not happen again."

The appearance of the video on television channels under such tight Kremlin control raised suspicions that it was done intentionally to cause alarm in the West.

Putin has held four meetings on defense issues in as many days this week, reflecting the close attention he is paying to military modernization at a time of heightened tensions with the United States and Europe over the crisis in Ukraine.

At Monday's meeting, he said Russia's military modernization program had been successfully implemented, with defense plants churning out new jets, missiles, navy ships and other weapons.