BEIRUT (Reuters) - A U.S.-backed campaign against Islamic State in eastern Syria will accelerate now the jihadist group has been defeated in its former capital Raqqa, a spokesman for U.S.-allied Syrian militias said on Wednesday.

The Syrian Democratic Forces (SDF), which announced the defeat at Raqqa on Tuesday, will redeploy fighters from the city to frontlines with Islamic State in the eastern province of Deir al-Zor, Talal Silo told Reuters by telephone.

Islamic State is already losing ground rapidly in Deir al-Zor, the last region where it has a significant foothold in Syria. The SDF and the Syrian government, backed by Russia and Iran, are fighting separate campaigns against the group there.

Silo said the Raqqa victory would have a “positive impact” on the SDF’s campaign in Deir al-Zor because it meant fighters could be redeployed as internal security forces take control of Raqqa.

“Most of the military forces will head towards these areas to continue the participation in the campaign with the Deir al-Zor Military Council,” he said. The Council is a militia leading the SDF’s campaign in the province.

“This is all to the benefit of the campaign and accelerating the end of this campaign,” he said.

The SDF’s campaign has been focused on areas east of the Euphrates River, which bisects Deir al-Zor province. The government’s campaign has focused mostly in areas to the west of the river.

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The U.S.-led coalition and Russian military are holding face-to-face deconfliction meetings -- to prevent inadvertent clashes between planes and troops under their respective commands - though the campaigns have occasionally come into conflict near the Euphrates River.

The Syrian army and its allies are battling for control of the last remaining IS-held areas of Deir al-Zor city, and have also recently captured the town of al-Mayadin from IS.

The U.S.-led coalition said it would be pushing further into Deir al-Zor province to clear remaining Islamic State fighters, but there is no plan for SDF fighters to move into Deir al-Zor city itself.

“Our goal is to defeat (Islamic State) in Iraq and Syria and if there are still areas where they hold territory then we will do what we can to clear those areas,” Col. Ryan Dillon, the coalition spokesman, said.

The last major Islamic State-held town in Deir al-Zor is Albu Kamal, which is the last Syrian town before the Iraqi border.