Fighters from the Kurdish People's Protection Units (YPG) stand guard at the site of Turkish airstrikes near northeastern Syrian Kurdish town of Derik, known as al-Malikiyah in Arabic, on April 25, 2017.
Footage shot Friday night showed a long line of Turkish trucks carrying military vehicles driving to the border area.
They also attacked the positions of the Kurdish militia near the town of Sinjar.
USA -led coalition forces are patrolling the Turkish-Syria border after Turkish military jets struck Kurdish fighters early last week. Kurdish officials described USA troop movements as a "buffer" between them and Turkey. Turkish warplanes killed more than 20 fighters of Kurdish Peshmerga.
"Twenty of our fighters were killed and 18 more injured as a result of the Turkish airstrikes", YPG spokesperson Redur Xelil said on Tuesday, referring to the strikes at Qara Shouk.
Turkey has long complained about United States military ties with the Kurds, complaining they are all terrorists.
Kurdish officials said the patrols are to monitor the border and prevent an increase in tensions with Turkey, a North Atlantic Treaty Organisation member and USA ally. Another Kurdish activist said the deployment is ongoing, adding that it stretches from the Iraqi border to areas past Darbasiyah in the largely Kurdish part of eastern Syria.
But for the United States, the YPG is essential in the fight against IS jihadists. "Huge America, the coalition and Turkey can join hands and turn Raqqa in to an ISIS graveyard", he declared at a press conference in Istanbul.
Moreover, a Syrian YPG commander on Friday told Reuters that us forces would soon be monitoring the situation along the Syria-Turkey border.
The YPG forms the backbone of the US-backed Syria Democratic Forces.
Redur Khalil, the spokesman for the YPG in Syria, said Turkey is reinforcing its border posts opposite Tal Abyad as well as other border posts.
The objective is "to discourage escalation and violence between two of our most trusted partners in the fight to defeat" Daesh, the statement said, adding that all parties in the region should remain focused on defeating the terror group.
"We hope that this military mobilisation is not meant to provoke our forces or for another objective linked to entering Syrian territories". In a statement, the SDF said it had captured six more neighborhoods in addition to the radio station building from ISIS in the city of Tabqa, west of Raqqa.
Turkish President Recep Tayyip Erdogan and his wife Emine Erdogan sit inside their vehicle after their arrival at the airport in New Delhi, India, April 30, 2017. Turkish President Recep Tayyip Erdogan expressed confidence he would be able to open a "new page" in troubled relations with Washington at a meeting next month with his counterpart Donald Trump.
"We are seriously concerned to see USA flags in a convoy that has YPG rags on it", Erdogan told reporters at Istanbul's Ataturk Airport before leaving for a two-day visit to India.
The PKK, which has carried out a three-decade insurgency against the Turkish state, has camps in the mountains of northern Iraq, near the Turkish border.