Turkish President Recep Tayyip Erdogan accused the United States of supporting Kurdish armed groups that Ankara says executed 13 kidnapped Turks in northern Iraq, adding a US statement of condemnation was “a farce”.

“The statement made by the United States is a farce,” Erdogan said on Monday in his first public comments since the killing of 13 Turks, including military and police personnel.

“You said you did not support terrorists, when in fact you are on their side and behind them,” Erdogan said in televised remarks criticising the US State Department statement, which failed to accept Ankara’s account of the incident.

Erdogan’s comments came a day after Ankara said Kurdistan Workers’ Party (PKK) rebels had killed 13 captives — most of them Turkish soldiers and police officers — they had allegedly abducted in southeast Turkey and kept in an Iraqi cave.

The PKK has been waging an insurgency against the Turkish state since 1984 that is believed to have left tens of thousands dead.

The United States and Turkey’s other Western allies recognise the PKK as a terror group.

But Washington has supported another Kurdish militia in Syria that Turkey sees as an offshoot of the PKK.

Turkey this month launched a military operation against rear PKK bases in northern Iraq that Erdogan said on Monday was designed in part to free the 13 hostages.

At least 48 members of the Kurdish armed group were also killed during the operation, according to Turkey’s defence minister.