Azerbaijani and Armenian forces battled for a second day on Monday after dozens were killed in an outbreak of heavy fighting that has raised fears of an all-out war between the longtime enemies.

Armenia and Azerbaijan, two ex-Soviet republics in the Caucasus, are locked in a decades-long territorial dispute with deadly fighting erupting Sunday.

At least 24 people have died after deadly clashes between arch foes Armenia and Azerbaijan, as the latest violence in the decades-long territorial dispute sparked international calls Sunday to halt the fighting.

Former Armenian president Serzh Sarkisian on Tuesday goes on trial charged with corruption, nearly two years after he was ousted from power by a popular uprising following a decade in office.

Armenia's jailed former president goes on trial Monday over what prosecutors describe as a coup that led to bloody protests but he insists is a politically motivated case.

Turkish police on Wednesday blocked protesters trying to hold a commemoration in Istanbul of the 1915 massacres and forced deportation of Armenians.

Troops from the Ottoman Empire -- which preceded modern-day Turkey -- were responsible for mass killing of Armenians, but Turkey has always denied that the incident amounted to genocide.

The electoral bloc of Armenia's acting prime minister Nikol Pashinyan won a landslide victory in Sunday's snap parliamentary elections, which were triggered by the reformist leader seeking to cement his political authority in the post-Soviet country.

The bloc led by Pashinyan's Civil Contract party had 70.45 percent of the vote, and trailing in distant second place with 8.37 percent was the Prosperous Armenia party, according to results from 90 percent of precincts, the central election commission said.

European observers said Monday there was "credible information" that Armenia's parliamentary election at the weekend was marred by "vote-buying" and pressure on voters.

The election, won by the pro-Russian ruling Republican Party, was "tainted by credible information about vote-buying, and pressure on civil servants and employees of private companies," observers from the OSCE, the Council of Europe, and the European Parliament said in a joint statement following Sunday's polls.

Turkey on Monday strongly warned the German parliament against adopting a resolution recognizing the mass killings of Armenians under the Ottoman Empire as genocide, saying it could have repercussions for bilateral ties.

The German lower house of parliament is set to vote on Thursday on the resolution over the two years of slaughter from 1915, which carries the contested word "genocide" throughout the text.

An Azerbaijani soldier was killed in Nagorny Karabakh on Thursday, the first casualty in almost a week following the worst outbreak of violence in the disputed breakaway region for decades.

The army sergeant was killed while "preventing the enemy's next provocation along the line of confrontation," Azerbaijan's defense ministry said in a statement, referring to archfoe Armenia.