BEIRUT - Turkey warned Russia on Monday against violating its airspace during raids in Syria, as Nato condemned the “extreme danger” of such intrusions and urged Moscow to stop targeting civilians.

Turkey, a Nato member, protested to Moscow after its F-16 jets intercepted a Russian fighter that violated its airspace near the Syrian border at the weekend. Two Turkish jets were also harassed by an unidentified MIG-29 on the Syrian border, Turkey’s army said.

“Our rules of engagement are clear whoever violates our airspace,” Turkish Prime Minister Ahmet Davutoglu said. “The Turkish Armed Forces are clearly instructed. Even if it is a flying bird, it will be intercepted,” he added, while playing down the idea of “a Turkey-Russia crisis”.

US Secretary of State John Kerry said the incident had risked provoking a serious escalation. “We’re greatly concerned about it because it is precisely the kind of thing that had Turkey responded under its rights could have resulted in a shoot-down,” he said.

At an emergency meeting, Nato warned of the “extreme danger” of such violations and condemned the incursions. The alliance also expressed “deep concern” over Russia’s military build-up in Syria, urging Moscow to “immediately cease its attacks on the Syrian opposition and civilians”. Russia later played down the incursion, saying one of its aircraft had briefly entered Turkish airspace as a result of “unfavourable weather conditions”. “There is no need to look for some conspiracy theories,” a defence ministry statement said.

Turkey and Russia remain on opposing sides of the Syrian conflict, with Moscow one of the few allies of President Bashar al-Assad while Ankara backs a solution excluding the embattled leader.

Russian warplanes have been flying over Syrian territory since Wednesday, conducting air strikes on what Moscow says are IS group targets in the country’s northern and central provinces.

The strikes have been criticised by opposition backers such as the United States, which heads a coalition already conducting raids against IS in Syria.

Russia said its warplanes had carried out 15 sorties on 10 IS targets on Monday, adding that 10 facilities had been hit. The West has accused Moscow of mainly targeting moderate opponents of the regime. More than 40 of Syria’s most powerful rebel factions said Monday Russia’s air campaign had “cut the road to any political solution” and urged a regional coalition to fight the regime and its allies Russia and Iran.

Some of the statement’s signatories, like the Islamist Ahrar al-Sham and moderate Jaish al-Izzah, have been targeted by Russia. IS has seized large parts of Syria and neighbouring Iraq, committing atrocities including beheadings, rape and mass killings, and destroying archaeological and cultural heritage.

On Sunday the militants blew up the Arch of Triumph in Syria’s ancient city of Palmyra, the country’s antiquities director Maamun Abdulkarim said.

“This is a systematic destruction of the city. They want to raze it completely,” Abdulkarim told AFP.

UNESCO chief Irina Bokova denounced the latest demolition, which comes after the group razed other parts of the site, including the 2,000-year-old Temple of Bel. “Extremists are terrified by history and culture,” she said, vowing there would be “no impunity” for those responsible. Under IS’s extreme interpretation of Islamic law, artefacts are considered idolatrous and must be destroyed, although the group has also smuggled and sold antiquities.

Analyst Charlie Winter of the London-based Quilliam Foundation think tank said such destruction was a “low-risk, cheap” way for IS to raise its profile among potential new recruits and grab headlines.

Palmyra fell to IS in May, but the Syrian army has advanced towards the city from the west and there are fears IS may now speed up its razing of the ancient site.

IS has taken advantage of the chaos in Syria caused by the four-year civil war, which has killed more than 240,000 people and sent millions fleeing, to expand its influence in the country.

A year-long US-led air campaign has failed to vanquish the militants, and Western governments have warned Russia’s involvement could make things worse.

US Defence Secretary Ashton Carter said Russia was pursuing a “losing strategy” in Syria.

“Russia has escalated the civil war, putting further at risk the very political resolution and preservation of Syria’s structure of future governance it says that it wants,” he said.

Turkey, a key opposition backer, has pushed for a so-called IS-free zone in northern Syria that could provide safe haven to refugees.

Russia spoke out against any move to create a no-fly zone, with deputy foreign minister Mikhail Bogdanov saying “it is necessary to respect countries’ sovereignty”.