Armenia's President Serzh Sarkisian has urged international powers to step up pressure on Azerbaijan to avoid all-out war over the disputed Nagorny Karabakh region, accusing his nation's arch-foe of military "blackmail". "The danger of a new war is constant and will persist until Azerbaijan is persuaded that there is no military solution to the conflict," Sarkisian told AFP in an interview ahead of a visit to France. Fears that the decades-long Nagorny Karabakh dispute could escalate have risen since sporadic firing across the volatile frontline surged last April into the worst violence since a 1994 truce. A ceasefire brokered by Moscow stilled several days of bloodshed but long-standing mediators from Russia, the United States and France have since struggled to restart a stalled peace process. Sarkisian -- who will meet French President Francois Hollande in Paris on Wednesday -- accused his Azerbaijani counterpart Ilham Aliyev of sabotaging any progress by threatening to start fighting unless he gets his way. "He said Azerbaijan will not start a war if Armenia fulfils its demands. I said that this is blackmail, not a compromise," the Armenian leader said. Sarkisian urged Paris, Moscow, and Washington to "show what price one of the sides will pay if it initiates an attack." "That will have a sobering effect," he said. - 'A matter of time' - Baku and Yerevan have feuded over the Nagorny Karabakh region since Armenian separatists seized the territory from Azerbaijan in a war that claimed some 30,000 lives in the early 1990s. Energy-rich Azerbaijan, whose military spending exceeds Armenia's entire state budget, has repeatedly threatened to take back the breakaway region by force but Moscow-allied Armenia has vowed to crush any military offensive. The war ended in a fragile 1994 truce but the two sides never signed a firm peace deal and Sarkisian warned that fears of a new surge in fighting are growing. "Public opinion in Armenia is that the resumption of hostilities is a matter of time -- maybe weeks or months -- and the commander-in-chief and defence minister must be prepared that a war could start tomorrow," Sarkisian said. "I don't think a fresh war is an immediate threat, but nothing is ruled out when one deals with an unpredictable neighbour." - Regional titans - Any new war in Karabakh could pitch regional titans Russia and Turkey against each other in the Caucasus region that has historically been an arena of their geopolitical rivalry. Sarkisian also took aim at Armenia's longstanding foe Turkey, blasting Ankara's support for its traditional ally Baku over the Karabakh conflict. There are no diplomatic ties between Yerevan and Ankara, which in 1993 sealed its border with Armenia out of support for Turkic-speaking Azerbaijan. Turkey has also been angered by Yerevan's campaign to have the World War I-era mass killings of Armenians in the Ottoman Empire recognised as genocide. "At this point, the process of normalisation (with Turkey) is in an impasse," Sarkisian said. "They link normalisation with the Karabakh issue." Stressing that international pressure and military parity between Yerevan and Baku have so far helped to avoid a new war, Sarkisian also expressed concern over Russia supplying sophisticated weapons to Azerbaijan worth billions of dollars. "We take it painfully because Russia is our strategic partner." Moscow has sold weapons to both of the former Soviet nations but has a military alliance with Armenia.