Turkey’s President Recep Tayyip Erdogan has fired the first shot in what could prove to be a tense clash with Iran over a proposed land corridor that Ankara’s close ally Azerbaijan sees as essential to ending its conflict with Armenia.

Neighbours Turkey and Iran rarely come to verbal blows publicly but on June 14 Erdogan took the step of criticising Iran for strongly opposing the “Zangezur Corridor,” which would connect Azerbaijan to its Nakhchivan exclave through Armenia. Nakhchivan borders Turkey, thus the corridor would also mean a long-sought connection between Turkey and Azerbaijan proper, not to mention further connections for the Turks through to the Central Asian countries and China via Azerbaijan.

“Iran’s approach to this issue disappoints us and Azerbaijan,” Erdogan said while speaking to reporters on his way back from a visit to Baku, his first since he was re-elected on May 28.

“I wish that we can overcome this problem soon. If Iran would approach this positively, then Turkey-Azerbaijan-Iran would be linked to each other, and we can have a ‘Beijing-London’ line through land and railroads,” he added.

The Zangezur Corridor would cross Syunik, the southernmost Armenian province, and run parallel to Armenia’s border with Iran. Tehran clearly fears the operation of the corridor could hinder its trade flows with the South Caucasus and beyond and, perhaps more importantly, reduce its influence in what it regards as its backyard, while increasing Turkey’s influence.

The Pashinyan administration of Armenia has several times rejected Azerbaijan’s demands for the corridor during attempts to end the territorial conflict between the two countries centred on Nagorno-Karabakh.

Yerevan says it can only agree to conventional transport links between Armenia and Azerbaijan and that it must retain control over any corridor. Azerbaijani citizens and cargo passing through Syunik could not be exempted from Armenian border controls, it adds, rejecting the Azerbaijani proposals as they stand.

Iran’s increasingly strong defence of Armenia’s standpoint in relation to what is and is not acceptable in Syunik has  frustrated “brother nations” Azerbaijan and Turkey, though Erdogan invited Armenian PM Nikol Pashinyan  to Ankara to attend his inauguration for another term of presidential office in early June and praised Pashinyan for accepting the invitation. There were plenty of opponents of Pashinyan in Armenia who protested that he should not have attended the event.