The deployment of Irish peacekeepers to the central African country of Chad has been postponed until the New Year due to the lack of adequate air support.
It means that the arrival of the main body of 400 Irish troops will be delayed by about two months.
Earlier this year, the EU agreed to send about 4,000 peacekeepers to Chad to protect refugees from neighbouring Darfur and aid workers.
Most of the troops earmarked for the mission are from France.
Ireland promised 400 soldiers, and Irish officer Lt Gen Pat Nash was put in charge of the operation.
Members of the elite Army Ranger wing and engineers were due to travel to Chad to prepare a camp for the main group of Irish troops.
But the planned deployment has been dogged by problems. EU countries have not supplied enough planes, helicopters and medical backup. Chad is a poor, landlocked country with huge logistical challenges in moving equipment, personnel, food and water.
The security situation has also worsened in recent days with Government troops in Chad killing hundreds of rebels around 65km from where the Irish are due to be stationed.
This morning, the anti-government Union of Forces for Democracy and Development declared what they said was a 'state of war' against French military forces, and any other foreign soldiers who might be deployed there.
In the past few days, Fine Gael warned that the peacekeeping mission was fraught with danger. But the Minister for Defence and the Chief of Staff insisted the Defence Forces were taking no unnecessary risks in sending troops to Chad.
The rangers will not now be sent to Chad until January at the earliest, and the main group of 400 troops will not go until late February or March.
This afternoon the Defence Forces said the delay in sending troops was not unexpected, due to the shortage of what they called 'key enablers' like air support.
A spokesman said any delay is completely unrelated to action by rebel forces in Chad.
