Clare Nuttall in Almaty -

Presidential elections set for July 19 in the breakaway Nagorno-Karabakh Republic have been slammed by Azerbaijan as a "provocation". As voters in the tiny unrecognised republic choose between sitting President Bako Sahakian and his challenger Vitaly Balsanian, who has taken a lead in the polls, the wider outcome of the election has been a further increase in tensions in the volatile South Caucasus region.

The day before Nagorno-Karabakh's 98,772 registered voters went to the polls, Azeri Foreign Ministry spokesman Elman Abdullayev issued a statement saying that the election "is completely contrary to the efforts of Azerbaijan and international organizations for peaceful resolution of the conflict."

Under international law, Nagorno-Karabakh remains part of Azerbaijan, although it has been de facto independent since the early 1990s, when forces backed by the Armenian army fought off an attempt to bring the enclave back under Baku's control. Although a ceasefire agreement ended the bloody war in May 1994, Armenia and Azerbaijan have never signed a peace settlement, and there is a continued threat that small-scale border skirmishes could escalate into a full-blown conflict once more.

The EU High Representative Catherine Ashton has also criticised the poll. "I would like to reiterate that the European Union does not recognise the constitutional and legal framework in which they will be held," she said in a July 18 statement. "These 'elections' should not prejudice the determination of the future status of Nagorno-Karabakh in the negotiated general framework of the peaceful settlement of the conflict.

Fears of a new outbreak of war have increased in the build-up to the vote. Nine soldiers were shot dead in a series of border clashes between Armenian and Azeri soldiers on June 4-5. Although there have been no further shootings since then, a higher than usual level of activity has been reported along the line dividing Nagorno-Karabakh from Azerbaijan proper. On July 11, Azerbaijan started a week of military exercises near Nagorno-Karabakh. Speaking to APA on July 17, a spokesperson for the Azerbaijani State Civil Aviation Administration reiterated a threat to shoot down any planes violating Azeri airspace by flying to the republic's newly reconstructed Stepanakert airport.

That is a clear warning against any wider recognition of the July 19 election. Cautioning against engagement with the separatist republic, Abdullayev said that anyone visiting Nagorno-Karabakh to monitor the elections would be added to the Foreign Ministry's blacklist.

Meanwhile, gaining international recognition for Nagorno-Karabakh as an independent state is a key issue in Balasanian's campaign. The challenger, a commander in the war against Azerbaijan and Nagorno-Karabakh's former deputy defence minister, has also appealed to voters tired of the growing corruption under President Sahakian. Opinion polls in the run-up to July 19 indicate it will be a closer result than in previous presidential elections, with the Armenian press describing a "hot election campaign" in the separatist republic. The latest opinion poll, carried out by the karabakh-open.info website gives Balasanian more than 45% of the vote, with Sahakian on 33.2%.

The third candidate, Arkady Soghomonian, deputy rector of the Stepanakert branch of the State Agrarian University of Armenia, was on just 5%, while Valery Khachatrian, who was polling around 12%, withdrew his candidacy on July 10. Sahakian, who was elected in 2007, has presided over a period of rapid economic growth - the economy expanded by 9.1% in 2011. He says that if re-elected he will continue to develop the economy, with a special focus on the agricultural sector.

However, the incumbent's critics say he has failed to deliver in other areas, notably by allowing corruption to increase under his rule and failing to provide employment for demobilised soldiers. The issue has become so acute that a group of soldiers sent an appeal to Armenian President Serzh Sargsyan, asking him not to back Sahakian in the election, RFE/RL reports.

Despite the Azeri threats and international criticism of the election, within Nagorno-Karabakh the run up to the election has been calm, with the four candidates agreeing in advance to ensure a just and transparent vote. Balasanian's staff have, however, written to Nagorno-Karabakh's Central Electoral Commission claiming that Sahakian campaigners have intimidated voters and breached election rules.