The Azeri defense ministry said the opposing forces attempted to recover lost ground by launching counter-attacks in the directions of Fizuli, Jabrayil, Agdere and Terter.
The ministry said in a statement that in the morning there was fighting around Fizuli city and the Armenian army shelled the Dashkesan region on the border between the two countries, miles away from Nagorno-Karabakh.
Armenia denied those reports but reported fighting throughout the night and said Nagorno-Karabakh's army repelled attacks in several directions along the line of contact.
Nagorno-Karabakh is a breakaway region that is inside Azerbaijan but run by ethnic Armenians and supported by Armenia.
It broke away from Azerbaijan in a war in the 1990s, but is not recognized by any country as an independent republic.