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Russian and American troops are within “hand-grenade range” of each other in parts of Syria, according to U.S. commanders, an overlap that highlights Moscow's efforts to bolster its footprint in the Middle East.

While the Russians and Americans have traditionally been on opposite sides of the Syrian civil war — with the Kremlin supporting President Bashar al-Assad and Washington working with rebels fighting him. But now the rivals are both backing Kurdish YPG fighters as they take on ISIS there and in neighboring Iraq.

"Escalation is bound to happen"

Army Lt. Gen. Steven Townsend, the commander of Combined Joint Task Force Operation Inherent Resolve, told reporters earlier this month that all the forces in Syria “have converged literally within hand-grenade range of one another.”

American and Russian commanders are in contact as a result, according to U.S. Central Command, although the Pentagon stopped military-to-military cooperation after Russia’s annexation of the Crimean Peninsula.

This tentative cooperation is a result of Russian and American “short and midterm interests" which are "are overlapping to a huge extent,” said Andreas Krieg, a professor at the Defense Studies Department at King’s College London. “Fighting ISIS and fighting the jihadis is absolutely the first priority of the [Donald] Trump administration. This is why [Defense Secretary James] Mattis is going so hardcore after ISIS. And almost everything goes as long as they are fighting jihadis at the same time.”

There are big risks to this approach from an American perspective, according to Krieg. The Kurdish forces that the Russians and Americans are both fighting alongside do not take orders from the powers supporting them.

Russian soldiers gather as rebel fighters and their families leave Homs, Syria, on March 18. Omar Sanadiki / Reuters

“These surrogates are doing their own operations and then the sponsors are doing air cover and artillery cover,” he said.

Krieg warned that because of the close proximity, Americans or Russian troops could potentially be hit inadvertently despite fighting on the same side.

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"Escalation is bound to happen," he added.

It isn't known exactly how many Americans are fighting on the ground although the figure is believe to be under 1,000. That number may have been boosted by the arrival of several hundred more in recent weeks to support the battle to route ISIS from Raqqa, the extremists’ de facto capital.

The Kremlin has also not said how many Russians are fighting in Syria, although estimates published in the country's press run into from 1,600 to 4,500.

During the first two weeks of March, Russian and Americans both worked with Kurdish YPG fighters — longstanding U.S. allies in the war against ISIS — to stop the Turkish army from entering the town of Manbij. An eyewitness told NBC News that he saw Russian and Syrian as well as American forces outside the Kurdish town in separate bases, but around 3 miles from each other, on March 12. Americans forces are still there.

A YPG spokesman confirmed an "agreement” had been struck with the Russians near Afrin in the northeast of Syria close to the Turkish border on March 20.

Map showing the locations of Afrin (pin on left) and Manbij in northern Syria. Google

The Russians, meanwhile, are engaged in a broad public-relations struggle, internally and internationally, experts say.

“Russia would prefer to achieve great accomplishments,” according to Alexander Shumilin, the head of the Middle East Conflict Center at the Institute for U.S. and Canada Studies, a state-run research group in Moscow.

Russia's goal "is to get some concessions from the United States" which will allow it to maintain its military presence in the Middle East and the Mediterranean through bases in Syria, according to Igor Sutyagin, a senior research fellow at London's Royal United Services Institute think tank.

It wants “an alliance between Russia and the United States in fighting terrorism, and to be recognized as an equal partner with the United States,” both to strengthen its “international standing as a power and its position with its own people," he added.

For these reasons, Russia is risking a recent rapprochement with Turkey by working with Kurdish fighters, experts said. Ankara considers the YPG terrorists and fears that they will join forces with Kurds in Turkey to carve out a separate state.

Turkey is also a key U.S. ally and an important member of NATO — the key Western defense alliance — so angering them also carries its risks for Washington. In fact, while working with the Kurds, considered the most effective anti-ISIS force in the country, Americans have agreed to stay east of the Euphrates River as a concession to Turkey.

An American military vehicle is pictured on the outskirts of Manbij, Syria, on March 7. Arab 24 via AP

So it is a high-stakes game for the U.S. but especially Russia, whose rulers would have been forgiven for hoping that a Trump White House would improve relations after years of tensions under former President Barack Obama, analysts said.

The Russians are learning that under the new White House they have to "deliver a service or have nothing," RUSI's Sutyagin said. "It is becoming more and more evident that Trump ... would not be willing to cooperate with Russia without really substantial Russian contribution."

Jon Alterman, the director of the Middle East Program at the Center for Strategic and International Studies, warned against viewing the Russians as allies.

“The people in the military have been watching the Russians up close,” he said. The Russians “are not allies and they are not going to be allies.”

Alterman also suggested that Moscow's approach toward terrorism made it an unreliable associate.

“The way the Russians view counterterrorism is about cowing people into submission, which makes problems in the future,” he said.