LAGOS, Feb. 19 (Xinhua) -- The West African bloc ECOWAS condemns Thursday's coup in one of its members Niger, according to Nigeria's Acting President Goodluck Jonathan.

The Nigerian government, also a member of ECOWAS, condemns all acts of gaining power or remaining in power via unconstitutional means in Niger, the president said in response to the coup in Niamey, capital of Niger, where President Mamadou Tandja was seized by mutineers.

In a statement reaching here on Friday, Jonathan condemned the political unrest in that country.

The statement quoted Jonathan as calling on all Nigerien stakeholders, including the security forces, to resolve the constitutional crisis through dialogue and negotiations.

According to the statement, the Nigerian leader is consulting with the Chairman, AU Mediation Committee, President Abdoulaye Wade of Senegal, and Abdulsalam Abubakar, ECOWAS mediator, with a view to ensuring the speedy resumption of the inter-Nigerien dialogue.

In it reaction, the regional power bloc ECOWAS,said it rejects any change of power through unconstitutional means and violence in accordance with its protocol on Democracy and Good governance.

"In the same way ECOWAS had earlier condemned the change of the Constitution and the referendum held in August 2009 carried out by president Tandja," the statement said.

There had been political tensions in Niger since President Tandja dissolved the country's parliament and conducted a referendum to extend his two-term tenure.

The opposition condemned the Aug. 4, 2009 referendum that would allow Tandja, who was scheduled to step down in December 2009 after the expiration of two five-year terms, to stay in power till 2012.