File photo shows Turkish President Tayyip Erdogan attends a news conference following the talks with his Russian counterpart Vladimir Putin in Sochi, Russia, May 3, 2017. [Photo/Agencies]

ANKARA - Turkish President Recep Tayyip Erdogan said Wednesday he hoped Washington would "reverse" its decision to arm a Syrian offshoot of the Kurdistan Workers' Party (PKK) before his visit to the US next week.

Speaking on a joint press conference with Sierra Leone President Ernest Bai Koroma in Ankara, Erdogan said" A terrorist group cannot be defeated with another one,"quoted by local private broadcaster NTV.

"Everything that happens in Syria and Iraq is a matter of national security for Turkey,"he stated.

The president said he would express his concerns in this regard at the meeting with his US counterpart Donald Trump on May 16, adding the same issue would also be brought up at the NATO summit to be held in Brussels on May 25.

Meanwhile, during an interview with NTV, Turkish Defense Minister Fikri Isik said that US decision to supply weapons to Syrian Kurdish militants will "neither benefit the US nor the region".

"The delivery of heavy weapons to the People's Protection Units (YPG) is a crisis itself," Isik said.

He reiterated Turkey's stance of not joining any military operation in the region involving terrorist groups.

Turkish main opposition Republican People's Party (CHP) criticized on Wednesday the US decision, urging President Erdogan to cancel his upcoming visit to the US.

The opposition Nationalist Movement Party (MHP) also underlined the timing of the announcement, describing it as a move "beyond political disrespect, a mockery against Turkey."

On Tuesday, the Pentagon announced that US President Trump had approved the arming of the YPG "as necessary to ensure a clear victory" in a planned operation to retake the northern Syrian city of Raqqa from the Islamic State(IS).

Turkey considers the Democratic Union Party (PYD) and its armed wing, the YPG, to be the Syrian affiliates of the PKK, a terrorist organization listed by Turkey, the US, and the EU.

However, the US has supported the PKK and the PYD as its ally on the ground in combating IS in Syria.