BISSAU (Reuters) – Police in Guinea-Bissau’s capital used tear gas to disperse hundreds of protesters demanding fresh elections on Saturday as a regional mission pushed for the implementation of a deal to end a year-long political crisis.

President Jose Mario Vaz sacked his Prime Minister Domingos Simoes Pereira in August 2015 sparking infighting within the ruling PAIGC party that has left the West African nation’s institutions gridlocked.

Demonstrators, some of them carrying signs reading “Jose Mario Vaz Out!”, marched on the presidential palace in the capital Bissau, calling for parliament to be dissolved and new elections to be held before riot police intervened.

The former Portuguese colony is notoriously unstable, having experienced nine coups or attempted coups since 1980. The turbulence has allowed it become a major transit point for cocaine trafficked from South America to Europe.

The United Nations has warned that the crisis might benefit drug traffickers and attract “extremist terrorist groups” seeking to gain a foothold in the region.

Rival factions agreed on a deal to end the political infighting last month, but implementation of the agreement has stalled.

Liberia’s President Ellen Johnson Sirleaf travelled to Bissau on Saturday at the head of a delegation from the regional bloc ECOWAS, which helped mediate talks over the agreement.

After discussions the delegation implored all parties to live up to the terms of the deal, including the appointing of a prime minister to name a new inclusive government and parliamentary approval of its programme.

It also called for a national dialogue in the aim of agreeing a political stability pact as well as constitutional and institutional reforms ahead of the next scheduled elections in 2018.

(Reporting by Alberto Dabo in Bissau; Writing by Joe Bavier in Abidjan; Editing by Tom Brown)