BRUSSELS • Nato has rejected Moscow's explanation that its warplanes violated the air space of alliance member Turkey by mistake and said Russia was sending ground troops to Syria, a claim dismissed by Moscow.
With Russia extending its air strikes to include the ancient city of Palmyra, Turkish President Tayyip Erdogan said he was losing patience with Russian violations of his country's air space.
"An attack on Turkey means an attack on Nato," he warned at a Brussels news conference.
Nato Secretary-General Jens Stoltenberg said yesterday the alliance had reports of a substantial Russian military build-up in Syria, including ground troops and ships in the eastern Mediterranean.
"I will not speculate on the motives... but this does not look like an accident and we have seen two of them," Mr Stoltenberg said of the air incursions over Turkey's border with Syria. He noted that they "lasted for a long time".
The incidents underscore the risks of a further escalation of the Syrian civil war as Russian and US warplanes fly combat missions over the same country for the first time since World War II.
The Russian Defence Ministry had said that an SU-30 warplane had entered Turkish air space along the border with Syria "for a few seconds" last Saturday, a mistake caused by bad weather.
Nato said a plane also entered Turkish air space on Sunday, an incident Russia said it is looking into.
Russia's Nato envoy Alexander Grushko said the alliance was using the accidental incursion to distort the aims of Moscow's air campaign in Syria, according to the Tass news agency.
The United States, leading the coalition attacking the Islamic State in Syria and Iraq (ISIS), wants to avoid being drawn into a proxy war with Russia, which is defending its ally, Syrian President Bashar al-Assad.
Russian President Vladimir Putin has said he would not put ground forces in Syria.
But Mr Stoltenberg said: "I can confirm that we have seen a substantial build-up of Russian forces in Syria: air forces, air defences, but also ground troops in connection with the air base they have, and we also see an increased naval presence."
Pressing ahead with an air campaign that began nearly a week ago, Russian jets hit ISIS targets in Palmyra and the northern province of Aleppo, Syrian state television said, in some of the heaviest Russian attacks on the militant group.
Security think tank Quilliam, in a study, said most ISIS propaganda now aims to prove it is a genuine nation, rather than glorify acts of violence.
ISIS media teams produced 900 separate reports, videos and radio programmes in one month, and 469 of these focused on civilian life and statehood, BBC yesterday cited the study as saying.