BRUSSELS European Union countries have started laying the groundwork to slap the first sanctions on members of the Niger junta that seized power in the West African country last month, sources told Reuters on Wednesday.

The new military leaders have so far rejected international diplomatic efforts at mediation. Neighbouring countries backing the armed takeover called on the United Nations to prevent a military intervention threatened by other West African states.

An EU official involved in sanctions work and an EU diplomat said the bloc has started discussing criteria for punitive measures. The official said that would include "undermining of democracy" in Niger and was likely to be agreed soon.

"The next step would be sanctions against individual members of the junta" deemed responsible, said the EU diplomat.

National officials were discussing the matter on Wednesday, said the official and another EU diplomat.

All three sources spoke under condition of anonymity.

(Reporting by Gabriela Baczynska, additional reporting by Andreas Rinke in Berlin and Crispian Balmer in Rome; Editing by GV De Clercq)