PENTAGON - The U.S.-led coalition to defeat Islamic State in Iraq and Syria has confirmed that Syrian military forces have made it to the Islamic State-held city of Deir el-Zour.

Coalition spokesman Army Col. Ryan Dillon told reporters Thursday the Syrian military had arrived on the outskirts of the city and “linked up with their besieged brigade” that had been trapped in the city for nearly three years.

The coalition estimates there are some 2,500 ISIS fighters in and around Deir el-Zour, which lies on the eastern end of the Middle Euphrates River Valley.

The U.S.-led coalition has been conducting airstrikes against Islamic State in Deir el-Zour province, but so-far has left clearing the province of the terrorists to the Syrian regime and its Russian partners.

A recent deal brokered between the Syrian government, Hezbollah and Islamic State meant to allow Islamic State fighters and their families to take a convoy of buses to the Iraqi border, however, has raised additional concern about the Syrian government’s determination to defeat the group.

The deal, which neither the coalition nor the Iraqi government agreed to, was intended to provide safe passage to the Iraqi border for hundreds of Islamic State fighters and their family members.

“Yes, there is concern about whether or not and how serious the Syrian regime is about defeating ISIS,” Dillon told reporters Thursday, adding that the U.S. would not allow the Syrian government to merely push Islamic State fighters to another country.

Dillon said Syrian Democratic Forces, along with an Arab contingent from the area, are “still prepared to seize hometowns in the province of Deir el-Zour from ISIS,” even as the Syrian military has advanced to Deir el-Zour city.

“We’ll just have to see when that is going to happen,” Dillon said.

At the United Nations, the Syrian government said road access to some areas of Deir el-Zour now have reopened as a result of the Syrian military’s advance. U.N. spokesman Stephane Dujarric said the area previously had been reachable only by World Food Program airdrops.

Israel kills 2 Syrian soldiers

Meanwhile, Syria's army says Israeli warplanes attacked a Syrian military position early Thursday near the town of Masyaf, killing two soldiers and causing material damage.

The army statement said Israeli forces fired missiles while in Lebanese air space. Masyaf is located in Hama province, near the Mediterranean Sea about 40 kilometers north of the Syria-Lebanon border.

The Israeli military did not comment on the reported attack, which has been its usual response to similar attacks during the Syrian conflict. Israeli officials have, though, confirmed in the past that strikes inside Syria have targeted weapons shipments believed to be headed to the Lebanon-based militant group Hezbollah.

Hezbollah forces have fought in Syria in support of President Bashar al-Assad's forces.

The Britain-based Syrian Observatory for Human Rights, which monitors the fighting in Syria, said the strikes hit a scientific research center and a nearby camp where surface-to-surface missiles are stored.