RMEILAN/GENEVA: Kurdish-controlled areas of northern Syria are expected to declare a federal system on Thursday, a move likely to further complicate peace talks in Geneva aimed at ending more than five years of war.

Russia pulled more warplanes out of Syria, a new delivery of humanitarian aid reached northern Aleppo province and UN mediator Staffan de Mistura named a Russian academic to his team of advisers in a nod to Moscow's importance in brokering an end to the fighting.

But despite a more than two-week-old "cessation of hostilities" and Russian President Vladimir Putin's decision to pull out some of his country's forces that have tipped the balance of the war in Syrian President Bashar al-Assad's favour, any hopes of a breakthrough at the peace talks in Geneva remain slim.

Russia's Defence Ministry on Wednesday reported 10 new ceasefire violations and the Kurds, after being excluded from the talks in Geneva, appeared to be taking matters into their own hands by drawing up plans to combine three Kurdish-led areas of northern Syrian into a federal arrangement.

The three areas already have de facto autonomy and while it was unclear what the new system would entail, there was no indication it would involve a separation from Syria.

The new arrangement, which a conference in the Kurdish-controlled town of Rmeilan agreed would be announced on Thursday, would alarm neighbouring Turkey, which fears growing Kurdish sway in Syria is fuelling separatism among its own minority Kurds.

"Syria's national unity and territorial integrity is fundamental for us. Outside of this, unilateral decisions cannot have validity," a Turkish Foreign Ministry official said.

The United States said on Wednesday it opposed Syrian Kurds forming an autonomous region in northern Syria, but could accept such an arrangement if the Syrians collectively agreed on it.

The Syrian Kurdish YPG militia have been an important ally in the U.S.-led military campaign against Islamic State in Syria, and this has been a point of friction between the United States and its NATO ally Turkey.

However, Bashar Ja'afari, head of the Syrian delegation in Geneva, rejected any talk of a federal model for Syria and ruled out direct talks with the main opposition delegation. The main opposition group's chief negotiator, Mohamad Alloush, said it had not yet decided whether it would hold direct negotiations with "the regime delegation".

Ja'afari also said Putin's announcement of a partial withdrawal of his armed forces on Monday had come as no surprise to the Syrian government, describing it as "common decision, taken both by President Putin and President Assad".

SYRIA POSITION UNCHANGED

Some Western officials and commentators speculated Putin intended the partial withdrawal to force Damascus to soften its position at the talks to improve chances of progress, but Ja'afari signalled no change in its stance.

Yet Putin's announcement surprised the West. He cited Russian military success in Syria as the reason for the drawdown, but his belief that the intervention delivered him a seat at the top table of world affairs may have tipped his hand.

De Mistura's appointment of Vitaly Naumkin plays into this narrative. A former Soviet army officer, Naumkin is an expert on Islam and the Arab world and served as a moderator at earlier peace talks on Syria that were held in Moscow.

But talking about the latest round of talks last week, Naumkin told Russia's RIA news agency: "There are no expectations. It is a difficult, complicated negotiation process."

The Geneva talks are part of a diplomatic push launched with US and Russian support to end a conflict that has killed more than 250,000 people, created the world's worst refugee crisis, and allowed for the rise of Islamic State.

US-Russian cooperation has already brought about a lull in the war via the "cessation of hostilities agreement", though many violations have been reported.

The Russian Defence Ministry said on Wednesday that in the preceding 24 hours there had been four violations in Aleppo province, three in Latakia and one each in Idlib, Homs and Hama.

Opening the indirect talks on Monday, de Mistura said Syria faced a "moment of truth", and he has described Putin's decision to withdraw some Russian forces as a "significant development".

Regional foes Saudi Arabia and Iran, which are deeply at odds over Syria, welcomed Putin's move and the Arab League said it would help the UN-mediated talks to end the conflict.

Just under half of Russia's fixed-wing strike force based in Syria has flown out in the past two days, according to Reuters calculations based on state television footage.

The precise number of planes that Russia kept at its Hmeymim base in Syria's Latakia province is secret. But analysis of satellite imagery, air strikes and Defence Ministry statements suggested it had about 36 fixed-wing military warplanes there.

In the past two days, at least 15 of those planes - including Su-24, Su-25, Su-30 and Su-34 jets - have been seen on television flying out though Reuters could not independently verify the movements of the aircraft.

RUSSIAN JETS IN ACTION

Despite the partial withdrawal, Russian warplanes have been carrying out new sorties against positions belonging to Islamic State, which is not covered by the cessation of hostilities.

RIA said Russia had also started supplying weapons to Iraqi Kurds, including five Zu-23-2 anti-aircraft cannons and 20,000 shells for the cannons.

British Foreign Secretary Philip Hammond said his country was not sure Putin's drawdown announcement was genuine.

"We've seen before, in Ukraine, Russia talking about a withdrawal, and then it turned out to be merely a rotation of forces," he said during a visit to Baghdad, adding he could not foresee "enduring peace" with Assad in power.

Moscow has rejected calls for Assad to be forced to step aside. He also still enjoys military backing from Iran, which has sent forces to Syria along with Lebanon's Hezbollah.

The United States has also been carrying out air strikes in Syria. An Islamic State-linked website said the jihadist group had shot down a military plane near Kirkuk in Iraq, but US officials said they knew nothing of such reports.

Under the cessation of hostilities, fresh humanitarian aid has reached areas hit by recent fighting. A new convoy of 26 trucks brought aid to about 13,000 families in northern Aleppo province, the Red Cross said.

The delivery by the Syrian Red Crescent to towns including Azaz, Afrin and Tal Rifaat was the largest in the area for weeks, Red Cross spokesman Pawel Krzysiek said. Clinics had been resupplied in the meantime, he said.

On the second day of talks in Geneva on Tuesday, opposition negotiators demanded that the government detail its thoughts on a political transition in Syria and said there had been no progress on freeing detainees.

The moves in Rmeilan, which was discussing a "Democratic Federal System for Rojava - Northern Syria", further complicated hopes of progress in Geneva. Rojava is the Kurdish name for northern Syria.

Syrian Kurds effectively control an uninterrupted stretch of 400 km (250 miles) along the Syrian-Turkish border from the Euphrates River to the frontier with Iraq, where Iraqi Kurds have enjoyed autonomy since the early 1990s. They also hold a separate section of the northwestern border in the Afrin area.