The European Union military force heading for eastern Chad and the Central African Republic has resumed its deployment.
More than 200,000 refugees from Sudan are in camps in Chad
The EUFOR mission said a military transport plane had arrived in the town of Abeche in eastern Chad, and more would follow in the coming days.
Their deployment was delayed when rebels attacked the Chad capital.
The force of almost 4,000 troops expects to be operational by the end of the month.
It has a UN mandate to protect civilians and refugees from violence in the Darfur region of Sudan, and to provide security for humanitarian agencies.
Sudan has accused Chad of using refugees from Darfur as bargaining chips in the growing dispute between the two countries.
On Monday, Chad's Prime Minister Nouradine Delwa Kassire Koumakoye said his country could not absorb any more refugees, after 12,000 more people fled into Chad after attacks on villages in Darfur by Sudanese forces pursuing rebel fighters.
A team of UN and African Union investigators has found that two towns in the Sudanese region of Darfur were partially destroyed in an attack by government forces and their militia allies on Friday.
Sources close to the investigators say they found buildings burned to the ground, and they were told by residents that they'd been attacked by men on horseback.
An estimated quarter of a million refugees live in camps near the Chad-Sudan border after fleeing the conflict in Darfur.
Mr Koumakoye told reporters in the capital, N'Djamena, the international community should return the refugees to Sudan or move them elsewhere or the Chadian authorities would do it themselves.
Sudan denies accusations by Chad that is was behind last week's failed coup attempt by the rebels.
Its refugee commissioner, Mohamed Ahmed al-Aghbash, said any move by Chad to expel Darfur refugees would be a violation of international laws.
"This is mere trading and bargaining on the issue of the Sudanese refugees along the borderline with Chad," he was quoted by Sudan's official news agency as saying.