YEREVAN/BAKU (Reuters) - Armenia’s defence ministry on Friday said Nagorno-Karabakh air defence systems had shot down an Azeri warplane and two drones, an online government platform reported, but Azerbaijan’s defence ministry denied the report. Fighting between Azerbaijan and ethnic Armenian forces continued for a sixth day in the heaviest clashes since the 1990s around the enclave of Nagorno-Karabakh, with both sides claiming to have inflicted significant damage on the other.