By James Marson and Alan Cullison

MOSCOW--The downing of the Malaysia Airlines flight is a major setback to Russian President Vladimir Putin's carefully balanced Ukraine strategy of making efforts to appear publicly hands-off amid allegations that Russia was providing armor and weapons to help rebels hold off Ukrainian forces.

That approach helped head off tougher sanctions from the West, but looks harder to maintain amid claims that Moscow has placed sophisticated arms in the hands of fighters not fully under Kremlin control and may even have provided the expertise to use those weapons.

Now, Western leaders arepressing for a real cease-fire and for Russia to seal off the border, both of which would be bad news for the rebels and an increasingly isolated Mr. Putin. Russia also has called for an immediate cease-fire and an investigation while saying nothing about sealing the border.

But Mr. Putin also was defiant Friday, showing no sign of backing away from separatists. Instead he blamed Kiev for downing Flight 17, saying Ukraine's military operation created the grounds for the incident. He reiterated calls for a negotiated solution to the three-month conflict, a move that could freeze the situation on the ground and give Russia the leverage it needs to halt Kiev's tilt westward.

Ukrainian and U.S. officials said Flight 17 was likely shot down by a Buk missile system, which could have come from Russia as part of large arms shipments in recent weeks. Moscow denies sending the weapons.

President Barack Obama laid blame on the separatists, saying evidence indicated that the plane was shot down by a missile launched from territory they control. European governments are considering a major expansion of sanctions as early as next week, officials said.

Mr. Putin's intransigence and willingness to risk more-serious sanctions reflects his determination to resist what he sees as attempts by the West to prise Ukraine from his grasp, beginning with the revolution that ousted a pro-Russia president in February, Western diplomats and analysts say.

"He hasn't changed his position. In his view, it's a global geopolitical confrontation," said Alexei Makarkin, deputy head of Center of Political Technologies in Moscow. "He is sure that there was a revolution organized by the West, and that Russia has to confront it."

Even if he wanted to turn the ship around, he would face obstacles. Diplomats say hard-liners in the Kremlin are pushing for a more aggressive confrontation.On Friday, Russian state television gave little airtime to the explanation that the rest of the world thinks most likely, instead running reports suggesting that the airliner could have been shot down by a Ukrainian fighter, or that the real target could have been a plane in the area around the same time that was carrying Mr. Putin on his return from a trip to South America.

As details emerged on Friday of the Malaysia Airlines catastrophe, the Buk missile system that was responsible for the crash appears to have been part of a surge in weapons deliveries that the U.S. had flagged three days earlier, accusing Moscow of increasing its shipments of advanced arms to separatist rebels.

Although both Ukraine and Russia have Buk long-range antiaircraft systems, "I would think it improbable the system would not have been provided by the Russians," said Steven Pifer, director of Arms Control and Non-Proliferation at the Washington-based Brookings Institution.

On Friday, Ukraine's security service released what it said was evidence that the Buk system was delivered to Ukraine early Thursday morning near the Ukrainian village of Sukhodolsk and then parked near the village of Pervomaiske.

Within hours, it had launched its missile, the Ukrainians said, and then departed again for Russia. Ukraine's government released a brief video of what it said was the missile battery departing Ukraine, with one of its mounted rockets missing from its launchpad.

Rebels operating in Ukraine have said since the downing of Flight 17 that they don't have the sophisticated weaponry to take out a plane at such an altitude. But on June 29, separatists said they overran a Ukrainian military base, and acquired a Buk missile system, although Ukrainian officials denied the system had been seized.

In recent days, the rebels had claimed responsibility for shooting down a number of fixed-wing Ukrainian aircraft. Kiev officials insist that the rebels couldn't have shot down those aircraft without Russian help. The Buk system, known in the West as the SA-11, requires a highly trained crew that also can operate radar. It is doubtful that the rebels could have such a crew available to operate the SA-11, U.S. officials say.

That has contributed to speculation that the missile launch Thursday was done by Russian personnel in Ukraine or even personnel on the Russian side of the border.

"Because of the technical complexity of the SA-11 it is unlikely that the separatists could effectively operate the system without assistance from knowledgeable personnel," U.S. Ambassador to the United Nations Samantha Power told the U.N. Security Council. "Thus we cannot rule out technical assistance from Russian personnel in operating the system."

(END) Dow Jones Newswires

July 18, 2014 21:38 ET (01:38 GMT)

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