DAMASCUS (Dispatches) – U.S.-backed Kurdish militants said they captured a major oil field in Dayr al-Zawr province on Sunday, pressing their offensive in eastern Syria which has raised fears of a confrontation with government troops.
The so-called Syrian Democratic Forces (SDF) said its fighters took al-Omar field on the eastern bank of the Euphrates river in the early hours.  
With the support of airstrikes and special forces from the U.S., the SDF has been rushing to gain as much as territory as possible in oil-rich Dayr al-Zawr, bordering Iraq. The group has been focused on territory east of the river, which bisects the province.
Al-Omar oil field lies about 10km north of the town of al-Mayadin, which government troops and their allies took earlier this month. The town had turned into a major base for Daesh after they left Raqqah under a deal with U.S.-backed militants.
The so-called Syrian Observatory for Human Rights said Daesh terrorists who had withdrawn from the oil field mounted a counter-attack overnight against government forces. The militants made some gains around al-Mayadin, the Britain-based monitor said.
A Syrian military source denied this, saying there was no significant attack and fighting raged on at the same pace.
Any attack by Daesh there was a "desperate attempt," the source said. "The Syrian Arab Army is attacking, hitting Daesh positions ... and advancing," the source said.
U.S. President Donald Trump said on Saturday a transition can soon begin to set conditions for the administration of Syria now that the end of Daesh "caliphate is in sight" with the fall of Raqqah.
"We will soon transition into a new phase in which we will support local security forces, de-escalate violence across Syria, and advance the conditions for lasting peace, so that the terrorists cannot return to threaten our collective security again," he said in a statement.
Kurdish militants in neighboring Iraq have also overrun territory, putting themselves on a collision course with the central government after their aborted bid to control the oil-rich Kirkuk.
On Thursday, Kurdish militants held a "victory” parade in Raqqah, during which they put up a huge poster of Abdullah Ocalan, the jailed leader of the Kurdistan Workers’ Party (PKK) that is outlawed in Turkey.
Turkish Prime Minister Binali Yildirim said the raising of the Ocalan banner by the U.S.-backed Kurdish forces was proof that Washington "is not only cooperating with terrorists, but they are endangering the future of Syria.”
It came after Saudi Arabia’s Persian Gulf Affairs Minister Thamer al-Sabhan and U.S. special envoy to the Syria war coalition Brett McGurk visited Raqqah.
In his statement on Saturday, Trump described the capture of Raqqah a "critical breakthrough" but Russia said the Syrian city "inherited the fate of Dresden in 1945, razed to the ground by Anglo-American bombings."
The Russian Defense ministry said that Western countries were pumping humanitarian aid into Raqqah in a bid to mask the degree of destruction inflicted on the city.