The Diet on Wednesday endorsed the controversial Japan-India civil nuclear cooperation agreement that will allow the nation's firms to export nuclear materials and technology to India for nonmilitary use.

The pact has been a source of contention at home and abroad because India is neither a signatory of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) nor of the Comprehensive Nuclear Test Ban Treaty.

Opposition lawmakers argue that the accord will damage the credibility of the NPT system and help India acquire nuclear technology and materials.