Chad's government and four Sudan-based Chadian rebel groups signed a "definitive peace accord" in Libya on Thursday that included an immediate ceasefire, a Chadian presidency official said. The deal, which aimed to end more than two years of sporadic fighting in eastern Chad, was signed in the Libyan city of Sirte in the presence of Chadian President Idriss Deby, Sudanese President Omar Hassan al-Bashir and Libyan leader Muammar Gaddafi, the official, who asked not to named, told Reuters.

The head of the U.N.'s refugee agency has welcomed an EU decision to send 3,000 peacekeepers to eastern Chad, saying it would contribute to efforts to help civilians fleeing violence in neighboring Sudan. "It is a key instrument to allow for the security of the refugees ... and for the possibility of a more effective humanitarian operation," said Antonio Guterres, the U.N. high commissioner for refugees.

Chadian rebels attacked government troops in the eastern town of Goz Beida on Thursday, humanitarian workers said, just two days after the government declared a state of emergency in the remote border region. "Since 5 p.m. (1600 GMT) there has been shooting on the streets and fighting in town," said one Goz Beida resident who works for a foreign aid agency.

Tens of thousands of uprooted people have welcomed plans for the creation of a UN-mandated multi-dimensional mission to protect civilians and facilitate humanitarian aid in volatile parts of Chad and Central African Republic. But many fear it will come too late to prevent more attacks on refugees and internally displaced people (IDPs).

Four Chadian rebel groups initialled a peace agreement with the government on Wednesday at talks in Libya, a Chadian official said, but the leader of the main faction said there were many points left to resolve. "The contents are secret. An agreement should be officially signed very soon in a ceremony that will bring together heads of state in Tripoli," a senior Chadian government official, who asked not to be named, told Reuters in Chad's capital N'Djamena.