NATO Secretary General Jens Stoltenberg called on Russia to “avoid escalating tensions” with NATO following an incursion into Turkish airspace, speaking before a meeting of NATO defense ministers in Brussels on Oct. 6. (YouTube/NATO)

Russia and the United States tentatively agreed Tuesday to resume talks on how to prevent conflicts between their warplanes in the skies over Syria, even as concerns mounted about the potential for a broader confrontation in the Middle East between the two powers.

After days of complaints from U.S. and NATO officials about a lack of cooperation and risky maneuvers by Russian warplanes, Russia’s Defense Ministry offered to hold another round of discussions with the Pentagon on avoiding a midair disaster or a hostile encounter involving their fighter jets, drones and other aircraft over Syria.

The tone expressed by both sides remained distrustful, however, as they labored to agree on when to meet and accused each other of blocking progress. The dispute has escalated in recent days as Russia has ramped up its bombing campaign in Syria, further congesting a war zone that was already crowded with a dizzying array of foreign forces.

Russian warplanes based in Syria have twice violated the airspace of neighboring Turkey, a NATO member, adding to concerns about the potential for an inadvertent collision or confrontation.

NATO leaders have called the airspace incursions a deliberate act by Russia and are scheduled to meet Thursday in Brussels to discuss ways to counter Moscow’s moves.

Meanwhile, the issue has surfaced at every stop made by U.S. Defense Secretary Ashton B. Carter this week during his travels in Europe.

On Tuesday, during separate visits to see U.S. troops stationed in Spain and Italy, Carter was asked repeatedly how the Pentagon intended to respond to the Russian intervention. Each time, he criticized the Kremlin for its strategy and what he described as its risky behavior but said Russia would not deter the United States or its allies from attacking the Islamic State in Syria and Iraq.

“We’re going to keep doing what we’ve been doing,” Carter told U.S. personnel stationed at Naval Air Station Sigonella in Sicily. “What they’re doing is not only wrong, it’s backwards.”

Washington has accused Moscow of trying to prop up Syrian President Bashar al-Assad, a critical ally, and targeting Syrian rebels backed by the United States and its allies.

Russia asserts that its main goal is to hit the Islamic State and other “terrorist” groups fighting in Syria’s civil war, which has continued for four years.

On Tuesday, Russia’s deputy defense minister, Anatoly Antonov, upped the ante. In addition to the proposed talks about airspace management, he called for wider discussions about some level of Russian partnership with the U.S.-led alliance against the Islamic State.

A photo from the Russian Defense Ministry’s official Web site shows a bomb being released from a Russian Su-24M jet fighter over Syria. (AP/AP)

“To our regret, the Americans narrow down our cooperation to technical issues of cooperation between our pilots during the assigned missions,” Antonov said in a statement.

U.S. officials reacted warily, saying they wanted to meet immediately to iron out concerns about aviation safety but also suggesting that the Russian offer to team up against the Islamic State was not genuine.

“We look forward to the formal response from the Russians and learning the details,” said Pentagon press secretary Peter Cook. “We stand ready to meet again to continue our earlier discussions as soon as possible.”

No ‘real explanation’

Pentagon officials first spoke with Russian leaders last week in a video teleconference about devising an arrangement to prevent air accidents or hostile encounters over Syria. But the talks did not get very far, and U.S. officials said that, until Tuesday, Moscow had ignored their requests to meet again.

The backdrop was further complicated by rising tensions and clashing agendas.

In Brussels, NATO Secretary General Jens Stoltenberg rejected Russia’s claim that recent incursions into Turkish airspace were accidental.

“It doesn’t look like an accident, and we’ve seen two of them over the weekend,” Stoltenberg said at a Brussels news conference, calling the incursions “very serious.”

Stoltenberg said he did not want to speculate on Russia’s motives but noted that NATO had not received any “real explanation.”

Moscow quickly pushed back. Russia’s NATO envoy, Alexander Grushko, said the military alliance was using an accidental incursion to “distort the aims” of Moscow’s nearly week-old air campaign in Syria, according to the Russian TASS news agency.

Earlier Tuesday in Spain, Carter added to Washington’s warnings by criticizing suggestions from Russian lawmakers that Moscow might send “volunteer” militia fighters to Syria.

Russia, the defense secretary said, “would simply be deepening their mistake in Syria” if ground forces joined the battles there. Such a move, he added, would only encourage opponents of Assad to attack Russian interests in the region.

“This is a very wrongheaded and backward approach and is sure to backfire,” Carter told reporters during a visit to Morón Air Base in southern Spain, where about 2,000 U.S. Marines and Air Force personnel are stationed. “It’s just going to fuel the Syrian civil war, and so it’s a serious strategic mistake on the part of the Russians.”

A top Russian lawmaker, Adm. Vladimir Komoyedov, insisted that Russia has no plans to send ground troops, the RIA Novosti news agency reported.

New ‘front line’

Russia appears to be establishing what amounts to a “front line” extending from the city of Hama to the port of Latakia, where Russian warplanes are operating out of an expanded air base, according to a senior U.S. defense official who spoke on the condition of anonymity to discuss apparent Russian military moves.

Rebel advances in the area earlier in the summer spurred Russia’s decision to intervene militarily on behalf of Assad’s government, which had begun to look increasingly wobbly as the civil war ground on. The rebel gains in a strategic area of northern Hama province called the Ghab plain had threatened to cut communications between the Assad family’s coastal heartland in Latakia and Damascus, the capital.

The United States has criticized Russia for attacking moderate rebels grouped under the umbrella of the Free Syrian Army, but it has given no indication that it is prepared to increase aid to them.

Russian Foreign Minister Sergei Lavrov responded by challenging the existence of moderate rebels. He called the Free Syrian Army “a phantom group,” adding that “nothing is known about it.”

Syrian state television reported, meanwhile, that Russian airstrikes Tuesday hit areas including the ancient city of Palmyra. Activists have accused the Islamic State of destroying antiquities in the area, such as the “Arch of Triumph” that was viewed by the Roman emperor Hadrian in the 2nd century.

But a Russian Defense Ministry spokesman strongly denied the reports from Moscow’s Syrian allies, saying no Russian airstrikes were carried out in Palmyra.

“Our planes in Syria do not strike populated areas and especially ones with architectural monuments,” Maj. Gen. Igor Konashenkov said, according to TASS news.

Murphy reported from Washington.

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