President Recep Tayyip Erdogan has accused the Syrian government of working to disrupt the military co-operation between Turkey and Russia and derail a ceasefire in Idlib province. During a phone conversation with Russia's president Vladamir Putin on Monday evening, which the Kremlin emphasised was initiated by Turkey, Mr Erdogan said that a recent sharp rise in military activity by the Syrian government was aimed at ending a ceasefire that was brokered at the end of last year. The northern province of Idlib is the last bastion of opposition to President Bashar Al Assad. Russia’s decisive intervention in the conflict in 2015 turned the tide in favour of the Syrian regime, which had lost swathes of territory to Isis and moderate factions. The province is home to around three million residents and it is at the centre of a ceasefire deal agreed between Moscow and Ankara, which has been endorsed by Iran. The accord has, however, been on the verge of collapse ever since. The Syrian regime and its Russian guarantors are eager to launch a full scale offensive on Idlib, which is controlled by a group aligned with Al Qaeda, bringing about a conclusive military victory for Damascus. Officials in Ankara, however, are worried that a final assault on Idlib would force millions of refugees to spill over Turkey’s southern border, with the country already hosting more than three million Syrians who have been displaced by the eight-year conflict. In recent weeks, the Syrian government has intensified fighting along the southern border of Idlib with Russian support, fuelling fears that a large-scale assault is imminent. The sharp rise in fighting has forced UN-affiliated aid groups to halt deliveries of aid to tens of thousands of people in regions affected by the fighting. The United Nations Office for the Co-ordination of Humanitarian Affairs earlier said that some 15 health facilities and 16 schools had been caught up in the latest round of Syrian government attacks, which had displaced nearly 200,000 Idlib residents. Mr Erdogan called on Russia as the Syrian regime’s closest ally to reel in attacks on civilian infrastructure during his conversation with Mr Putin, a detail which was not included in the Kremlin’s readout of the conversation. "The president also added that the ceasefire violations in the Idlib de-escalation zone are worrying, and the fact that schools, hospitals and civilians are targeted has no place in a proper fight against terror," Mr Erdogan’s press secretary, Fahrettin Altun, said of the conversation with the Russian president. The call between the Russian and Turkish leaders came ahead of a meeting between Mr Putin and US Secretary of State Mike Pompeo in the Black Sea resort city of Sochi on Tuesday, where Syria will be high on the agenda, according to US officials.