Indonesian officials have apologised to Papua New Guinea after an unexplained flight by an Indonesian military aircraft into PNG airspace.
On Saturday, the unidentified helicopter flew from Indonesia's Papua province over the military checkpoint at Wutung and continued five kilometres inland into PNG.
The Indonesian government had not released any notification for the flight which PNG's Defence Force subsequently voiced concern over.
The border was closed for a day as PNG citizens were recalled onto their side of the border for their safety.
The head of information at the Indonesian embassy in PNG, Richard Bharata, says the matter has been cleared up now.
"Of course we have apologised because that is our doing wrong, that one. Actually it's not intentional, doing that, going into PNG airspace, that our pilot was mistaken to do that one."