The military in Guinea-Bissau has called for calm after the deposed former leader and controversial presidential candidate Kumba Yalla occupied the presidential palace for several hours before being forced out.

Armed forces chief of staff Tagme Na Wai said a group of soldiers escorting Mr. Yalla had occupied part of the presidential palace early Wednesday, saying he was taking over the presidency.

The soldiers in the incident were identified as former peacekeepers from the United Nations mission in Liberia.

General Na Wai said several hours of occupation ended after army troops, the presidential guard and angry protesters surrounded the palace in the capital Bissau.  Mr. Yalla then apparently agreed to return to his home without any violence.

But the incident prompted street protests in front of Mr. Yalla's party headquarters and his home, with hundreds of angry youths saying they were tired of his antics.  Mr. Yalla's guards fired shots to keep some of the protesters away.  But protesters were able to enter the headquarters of Mr. Yalla's Social Renewal Party, breaking tables and chairs.

Senegalese President Abdoulaye Wade, who has been leading regional mediation efforts, said Wednesday in Dakar a postponement of the poll should now be considered. 

Mr. Yalla is from the country's biggest ethnic group, the Balante, but he lost popularity during his aborted elected term amid corruption and stifling poverty.  Even though he may be losing even more support, now, London-based Africa security expert, Richard Reeve, says he may also be exacerbating ethnic divisions.

"Kumba Yalla seems to represent the Balante ethnic group which is the largest and the most significant in the military albeit it's still very much a minority within the country as a whole, so I think he has his pool of support but I think overall it's far from the majority," he noted.

Wednesday's unrest came as European observers started arriving to begin their monitoring work of the now uncertain June 19 poll.

Mr. Yalla has previously said the election should be canceled because he still has 18 months left of his time in power when he was ousted in the coup in 2003.  There are 16 other candidates in the presidential election, including popular former military ruler Joao Bernardo Nino Viera.