Former leader Sali Berisha of the main opposition Democratic Party has created a grouping trying to move the party leader Lulzim Basha from the post, accusing him of being a ``hostage'' of Prime Minister Edi Rama of the left-wing Socialist Party.

Protesters stormed the ground floor of the building, using iron bars to open the main door and breaking windows. Tear gas was used from inside the building to move them away.

At least one injured person was seen.

Basha fired Berisha from the parliamentary group in September, which sparked an internal party fight between them.

That followed an intervention in May by U.S. Secretary of State Antony Blinken, who said in a statement that during Berisha's 2005-2013 tenure as prime minister, the politician ``was involved in corrupt acts ... using his power for his own benefit and to enrich his political allies and his family members,'' interfering in ``independent investigations, anticorruption efforts, and accountability measures.''

Blinken said that Berisha's ``corrupt acts undermined democracy in Albania.''

In December Berisha's grouping claimed to have held a referendum removing Basha from his post, but the move was not recognized by the official Democratic Party.