Bangladeshi authorities have summoned Burma's envoy to protest against violations of their airspace amid an exodus of Rohingya Muslims fleeing violence in the country.
Burma's presidential spokesman said there is no evidence of any trespassing and that Dhaka should have reached out to discuss its concerns instead of issuing public statements.
The Bangladesh Ministry of Foreign Affairs said Burmese drones and helicopters flew into Bangladeshi airspace on Sunday, Tuesday and Thursday.
It said a protest note was handed to the envoy on Friday evening. Bangladesh warned that the "provocative acts" could lead to consequences.
In Yangon, presidential spokesman Zaw Htay said that while Burma's military denied crossing into Bangladesh's airspace, the matter is being investigated. "We don't know exactly if they released that statement for political reasons," he said of Bangladesh's protest.
He added that his country was "transporting rations for displaced people for emergency assistance" in areas close to the border and that Bangladesh "needs to understand that as well".
Up to 400,000 Rohingya Muslims have fled what they described as indiscriminate attacks by security forces and Buddhist mobs in Rakhine state since August 25, when a Rohingya insurgent group attacked police posts and the military responded with "clearance operations".
The UN has described the violence against the Rohingya as ethnic cleansing - a term that describes an organised effort to rid an area of an ethnic group by displacement, deportation or killing.
Ethnic Rohingya have faced persecution and discrimination in majority-Buddhist Burma for decades and are denied citizenship, even though many families have lived there for generations.
The Burmese government says hundreds have died, mostly Rohingya "terrorists," and that 176 out of 471 Rohingya villages have been abandoned.
Rights groups like Amnesty International and Human Rights watch have said that they have evidence that Burmese troops were systematically targeting and setting Rohingya villages on fire over the last three weeks.
UN agencies fear continued violence in Burma may eventually drive up to 1 million Rohingya into Bangladesh.
Burma has insisted that Rohingya insurgents and fleeing villagers themselves are destroying their villages. It has offered no proof to back these charges.