Turkish President Recep Tayyip Erdogan speaks during a ceremony in Ankara, Turkey, Jan. 15, 2018. Turkish military will soon start a new operation in a besieged border area of Syria, Turkish President Recep Tayyip Erdogan said on Monday. (Xinhua/Qin Yanyang)

ANKARA, Jan. 15 (Xinhua) -- Turkish military will soon start a new operation in a besieged border area of Syria, Turkish President Recep Tayyip Erdogan said on Monday.

"We have finished our preparations and an operation could start at any moment," Erdogan said in Ankara.

The Turkish Armed Forces will resolve the Afrin and Manbij issue as soon as possible, he said.

The Turkish president also strongly slammed the United States over its plans to form a 30,000-strong border forces based on the Syrian Democratic Forces (SDF), dominated by the People's Protection Units (YPG).

"It is our duty to kill this terrorist army before it is born," he vowed.

The U.S.-led coalition against the Islamic State (IS) had issued a written statement to some media outlets earlier on Sunday, confirming it will set up a 30,000-strong new border security forces with the YPG-led SDF.

The coalition named the new army the Syrian Border Security Force. About 15,000 of the fighters will be SDF veterans as the fight against IS comes to a close. The remaining 15,000 will be recruited and trained in the near future.

Currently, 230 individuals are training in the inaugural class, according to the coalition statement.

Turkey sees YPG as the Syrian affiliate of the Kurdistan Workers' Party (PKK), a group Ankara considers as terrorist. However, the United States has supported the YPG as its ally on the ground in combating IS in Syria.