TUNIS, Sept 2 (Reuters) - Tunisia's state-run phosphate companies have announced an agreement to hire 2,800 new workers after protests over jobs halted production and threatened to stop exports, an official with the operations said on Friday.

Ali Houchati, an official with the Gafsa Phosphate business, said the decision to hire the workers had already been made, but was announced early because of the protests.

Prime Minister Youssef Chahed, who took office a week ago, vowed to take a hardline with protests in the phosphate sector that cost the state millions of dollars in lost revenue in recent years.

(Reporting by Tarek Amara; writing by Patrick Markey) ((pat.markey@thomsonreuters.com; +213-661-692993; Reuters Messaging: pat.markey.thomsonreuters.com@reuters.net))