A Syrian Democratic Forces fighter walks with his weapon in northern Raqqa province. Reuters/Rodi Said

Syrian Democratic Forces (SDF), the U.S.-backed Syrian militia, said Friday it was well-equipped to advance and lay siege to the city of Raqqa controlled by the Islamic State group, thanks to support from the U.S.-led coalition. The news comes after the announcement from President Donald Trump's administration about a conference with ministers from 68 countries to be held in Washington over two days on March 22 and 23, which will focus on defeating ISIS.

The U.S. army announced Friday its plans to send an additional 2,500 ground combat troops to a base in Kuwait to serve as the backup for coalition forces, besides the additional 400 troops to be deployed directly to Syria.

"The number of our forces is now increasing, particularly from among the people of the area, and we have enough strength to liberate Raqqa with support from the coalition forces. ... We have information that the enemy is moving part of its leadership outside the city, as it is also digging tunnels under the ground. We expect they will fortify the city and the terrorist group will depend on street warfare," Jihan Sheikh Ahmed, spokeswoman for the SDF, said in a statement, according to Reuters.

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The question on planning for the battle for Raqqa, the major ISIS stronghold in Syria and the main base of operations, located around 99 miles east of Aleppo, is yet to be answered. Although Turkey is a U.S. ally in the war against ISIS, tensions prevail between the SDF and Arab-backed forces directed by Turkey, deployed west of the Euphrates river. SDF comprises the Kurdish YPG militia who are deeply distrusted by Turkey as it considers them as equals to the Kurdish militants from the Kurdistan Workers Party (PKK) in Turkey who have been fighting for independence for the past 30 years.

Although the SDF dismissed any suggestions of Turkey playing a role in the final assault during meetings with U.S. officials last month, Turkey said Thursday that no decision on the matter has taken. The U.S.-led coalition also said that a Turkish role may be possible after discussions, according to Reuters.