WASHINGTON - Turkish President Recep Tayyip Erdogan said Sunday his government is "seriously saddened" by television footage showing U.S. military forces operating alongside Syrian Kurdish fighters that Ankara views as terrorists and Washington believes are the most effective fighting force against Islamic State jihadists.

Turkish forces last week launched airstrikes on Syrian Kurdish Peoples' Protection Units (YPG), which Ankara considers to be the Syrian affiliate of the Kurdistan Workers' Party, against which it has been waging a three-decade-long fight for control of southeastern Turkey.

People gesture at a U.S military vehicle travellin People gesture at a U.S military vehicle travelling in Amuda province, northern Syria, April 29, 2017. People gesture at a U.S military vehicle travelling in Amuda province, northern Syria, April 29, 2017.

The U.S. slammed the Turkish strikes, saying they were not approved by the U.S.-led coalition and "led to the unfortunate loss of life of our partner forces."

After the Turkish attack, the U.S. sent military vehicles with American flags to the Syrian side to patrol with YPG fighters, apparently to prevent further clashes.

"Unfortunately... the presence of an American flag along with the [insignia] of a terror organization called YPG in a convoy has seriously saddened us," Erdogan said in Istanbul before heading on a trip to India.

Turkey and the United States, NATO allies, have long disagreed about the role of the Syrian Kurdish fighters in trying to retake Islamic State strongholds in Syria and Iraq.

White House meeting



Erdogan said that when he meets with U.S. President Donald Trump at the White House on May 16 he hopes to change the American leader's mind about U.S. support for the Syrian Kurdish fighters.

"This needs to be stopped right now," Erdogan said. "Otherwise it will continue to be a bother in the region and for us. It will also bother us as two NATO countries and strategic partners."

The Turkish leader said that Ankara's forces might bomb the YPG positions again, at any time it wants.

"I said yesterday: 'We can come unexpectedly in the night.' I really meant that. We are not going to tip off the terror groups and the Turkish Armed Forces could come at any moment."