Increasing attacks on civilians in Sudan's conflict-torn Darfur region have forced tens of thousands of people to flee their homes this year — possibly more than 200,000, a senior U.N. official said Wednesday.

Assistant Secretary-General for Peacekeeping Edmond Mulet told the U.N. Security Council that the second phase of a government military offensive has resulted in the displacement of at least 78,000 people, according to humanitarian organizations.

He said the U.N. humanitarian office has received reports that an additional 130,000 people have been displaced, mainly in the Jebel Marra area of North Darfur where the heaviest fighting has been taking place, but it hasn't yet verified the numbers.

"There is also significant concern about reports of indiscriminate attacks against civilians" and other human rights violations, Mulet said.

Darfur has been in turmoil since 2003, when ethnic Africans rebelled, accusing the Arab-dominated Sudanese government of discrimination. Rights groups charge the regime retaliated by unleashing Arab militias on civilians, a claim the government denies.

Sudan's deputy U.N. ambassador Hassan Hamid Hassan blamed most of the violence and displacement on rebel attacks and tribal clashes.

Sudan ordered the more than 20,000-strong peacekeeping force out of Darfur late last year, but Mulet made clear that it will not be leaving quickly.

He said the proposed "exit strategy," being discussed by the U.N., AU and Sudan, requires council-endorsed benchmarks to be met, and is "premised on a political solution to the conflict based on direct talks between the parties, starting with a cessation of hostilities."