USA forces are also based in Tanf, southwest of Albu Kamal in the Syrian desert near the borders of Iraq and Jordan.
Syrian President Bashar Assad has blasted the USA presence in Syria, referring to it as an occupation.
"Thirty-eight non-Syrian fighters from regime loyalist militias were killed in the night-time raid on Al-Hari, on the Syrian-Iraqi border", said Observatory head Rami Abdel Rahman.
The Syrian Observatory for Human Rights, a UK-based monitoring group, said it had documented the deaths of 38 non-Syrian militia fighters, but that it did not know whether they were Iraqi or Lebanese nationals.
Details on the strike were still scant, but United States officials say no airstrikes took place by any coalition members in the area.
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If Germany finish as Group F runners-up, they could face Brazil in a clash of World Cup titans in the next round. "He's a fantastic player who had a fantastic game, but it's about concentrating on the team".
A drone attack by the US-led worldwide coalition killed 40 Syrian soldiers and allies and injured 30 in a desert area south of al-Bukamal, northeastern of Deir Ezzor province, on Monday. There were no immediate details on casualties.
The US has since denied that it was behind the attack.
But a coalition spokesman said it had not carried out any strikes in the area.
It said several people were killed and wounded but did not give a specific number or their nationalities.
The U.S. -led coalition uses air power and special forces to back an alliance of Syrian Arab and Kurdish militia fighting Islamic State northeast of Albu Kamal.
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Why Koepka didn't become a major star in golf, a fan favorite, the guy with big crowds following him, after he won the U.S. Defending champion: Brooks Koepka . "I was surprised", said playing partner Russell Henley. "I just needed a good start".
Throughout Syria's seven-year war, Israeli officials have disclosed scores of air strikes within the neighbouring country against suspected arms transfers to Hezbollah or Iranian deployments.
In the oil-rich province of Deir Ezzor, the US-backed Syrian Democratic Forces and Syrian government forces have carried out parallel but separate offensives against IS.
The deadliest incident was in February, when US-led coalition air strikes killed at least 100 pro-regime fighters in Deir Ezzor province, including Russians.
The mission of these forces was to protect and secure the border between Syria and Iraq and fight the remaining so-called "Islamic State" terrorists in the area.
Al-Hari lies on the western side, close to the river and the de-confliction line.
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One of the problems is that once rates reach rock bottom (which is pretty well where they are right now) the only way is up. This could be a good time for more young Americans to take out a Roth Individual Retirement Account or IRA for short.
"For the first time in four years, Dashisha, a notorious transit town for weapons, fighters and suicide bombers between Iraq and Syria, is no longer controlled by ISIS (IS) terrorists", Brett McGurk, the U.S. president's special envoy for the war against IS, said on Monday.