TEHRAN (Reuters) - Iran will not back down on its nuclear stance despite the threat of tighter sanctions, Iranian media quoted a government spokesman as saying on Sunday.

Britain, France, Germany and the United States are considering imposing sanctions that go beyond existing U.N. measures against Tehran over its nuclear programme, a British diplomat said on Friday.

Western powers fear Iran wants to build a nuclear bomb, while Tehran says it seeks to master nuclear technology for electricity.

'Our stance would not change with sanctions or the threat of sanctions,' the students news agency ISNA reported spokesman Gholamhossein Elham as saying.

'It is important that our country is ready to insist on its rights under any conditions.' ....