KHARTOUM (Reuters) - Sudan is ready to sign a peace agreement with a major rebel group in the longstanding Darfur conflict, a government official said on Thursday, just days after President Omar Hassan al-Bashir extended a unilateral ceasefire.


The development follows a U.S. decision to review a lifting of sanctions that have crippled the country's economy for two decades.


The accord is not expected to end the Darfur conflict as several other rebel factions have resisted peacemaking to date. The conflict erupted in 2003 when mainly non-Arab tribes took up arms against Sudan's Arab-led government.


The United States said last week it would unfreeze Sudan's assets and remove financial sanctions as a response to Khartoum's cooperation in fighting Islamic State and other Islamist militants, but would wait 180 days to assess progress on human rights and resolving conflicts such as in Darfur.


Talks to secure a lasting ceasefire in Sudan's three warring regions under a road map for peace collapsed last August.


Magdy Khalafalla, head of the government's office for peace in Darfur, said an agreement would be signed in Doha next week between the government and Sudan Liberation Second Revolution, a group led by prominent rebel figure Abu al-Qasim Imam.

The rebel group was not immediately available for comment.

The deal with Sudan Liberation Second Revolution will be added to a framework peace agreement the government put together in 2011 but which only a few groups have so far signed on to, Khalafalla said.

"This movement's inclusion will widen the area that enjoys peace in Darfur, especially in the Marra mountains area...We are optimistic that the coming period will see major developments in the peace process in Darfur."

(Reporting by Khalid Abdelaziz; Writing by Eric Knecht; editing by Mark Heinrich)