Sudanese President Omar al-Bashir has confirmed that government forces have been bombing northern areas of the troubled Darfur region.
Mr Bashir says rebel groups are undermining security in the region
In an interview with the BBC Arabic Service, Mr Bashir said the action did not breach a UN-brokered ceasefire signed earlier this month.
He said the government had no option but to use its armed forces in response to attacks by rebel groups.
Nearly four years of fighting in Darfur has killed some 200,000 people.
More than two million people have been displaced.
'Talk of violations'
Rebel commanders in northern Darfur said on Monday that government aircraft had hit three villages over the weekend - claims the Sudanese government strongly denied.
But in an exclusive BBC interview broadcast on Wednesday, President Bashir confirmed his troops had carried out the bombardments.
He said the government had no option but to strike as 80% of attacks on civilians in the region were carried out by rebels groups, undermining security.
"They are not supported by the government. The government is fighting them," he said.
After the signing of a peace agreement with a leading rebel group in May, rival rebels formed a new alliance called the National Salvation Front, he told the BBC.
President Bashir said the group had received "massive military support in full view of the international community" and set out to target those who had signed the peace deal.
Militias have since carried out large-scale attacks on Sudan Liberation Movement positions in northern Darfur, controlling its movements, the president said.
"We heard no condemnation of this movement or the countries supporting it.
"But as soon as we were forced to send armed troops to deal with it we heard talk of violations and a ceasefire breach," he said.
The announcement of the 60-day ceasefire came earlier this month but it is not clear exactly which rebel groups have agreed to it.
President Bashir has opposed a UN plan to send a hybrid UN and African peacekeeping force to Darfur.
Some 7,000 African Union troops already on the ground have not been able to stop the violence - mostly blamed on pro-government Arab militias.
The Darfur conflict began in 2003 after a rebel group began attacking government targets, saying the region was being neglected by Khartoum.
The rebels say the government is oppressing black Africans in favour of Arabs.