Armenia and Azerbaijan accused each other on Monday of violating a new U.S.-brokered ceasefire in fighting over the mountain enclave of Nagorno-Karabakh, casting doubt over the prospects of the latest international push to end a month of clashes.

Azeri President Ilham Aliyev said in a televised address that he wanted to resolve the conflict “by political and military means” and reiterated a demand that ethnic Armenian forces must agree to leave the region for fighting to stop, Reuters reported. 

Armenian Prime Minister Nikol Pashinyan wrote earlier on his Facebook page that the Armenian side “continued to adhere to the ceasefire.”