N'DJAMENA (Reuters) - Chad has launched a helicopter attack on Chadian rebels in Darfur and sent a military convoy to the region, according to humanitarian workers and an opposition group, after Sudan announced a military campaign to end rebellions in the area.
Conflict broke out in the Sudanese region a decade ago when mainly African tribes took up arms against the Arab-led government in Khartoum, which they accuse of discriminating against them.
Law and order has largely broken down in the region, allowing rebels from neighboring Chad to launch attacks on their homeland from inside Sudan.
Sources said that the attack, which took place on Thursday using Mi-24 helicopters from Chad's army, had targeted a group of Chadian rebels near Tissi, on the Sudan-Chad border.
"There were bombings in the area around Tissi on the Sudan side on Thursday. It was a line of Chadian rebels that were targeted," said a humanitarian source in the region who asked not to be identified.
A spokesman for Chad's rebel coalition, the Union of Forces of Resistance (UFR), had earlier said that over 200 Chadian military vehicles had crossed into Darfur.
Relations between Chad's President Idriss Deby and the president of neighboring Sudan, Omar Hassan al-Bashir, have in the past been strained, with Sudanese-backed rebels twice attacking the Chadian capital N'djamena since 2006.
But ties have since strengthened and, in the latest indication of closer cooperation, Deby this week sent an adviser to meet Bashir in Khartoum to discuss security in Darfur, according to Sudan's state radio.
Sudan's Defense Minister Abdel Raheem Mohammed Hussein this week announced to parliament a campaign aimed at ending rebellions in the Darfur region, according to the state-run news agency Suna.
"There is speculation that the Chadian soldiers have been deployed in support of Sudan's overall military plan to end the rebellion in Darfur," said a report by a Swiss-based NGO, the Darfur Relief and Documentation Center.
UFR could not immediately be reached to comment on the helicopter attack. Officials for the Chad government declined to comment.
The conflict in Darfur has killed 200,000 people and displaced two million.
So far this year, 460,000 people have been displaced by the violence, according to the United Nations.
(Reporting by Madjiasra Nako; Writing by Emma Farge; Editing by Toby Chopra)