TOKYO (Yonhap) -- The upper house of Japan's parliament passed a bill this week to strengthen its atomic regulations, but it also raised suspicion over nuclear armament by adding a contentious clause of "security guarantee" to the bill, a news report said Thursday.

The bill is aimed at creating an independent nuclear regulatory body following last year's atomic disaster at the Fukushima nuclear plant, but the clause may pave the way for Japan to produce nuclear weapons, the Tokyo Shimbun reported.

The Article 2 of the bill, approved on Wednesday, stated that Japan should secure the safety of nuclear use for the protection of people's lives, health and wealth as well as the nation's "security guarantee," according to the report.

Although Japan's constitution strictly prohibits it from producing, possessing and using nuclear weapons, its atomic infrastructure makes it eminently capable of building a nuclear arsenal at will.

Japan's Chief Cabinet Secretary Osamu Fujimura, however, denied the suspicion.

He told reporters later on Thursday that the bill "emphasized the peaceful use of nuclear power plants."

"There will be no military use of nuclear power," Fujimura said. "There is no change in our three principles for peaceful use of nuclear energy."

Those principles are never producing, possessing or allowing the entry of nuclear weapons.