Turkey is attacking Kurds outside the designated “safe zone,” violating this week’s agreement between Ankara and Russia, U.S. Senator for Maryland Chris Van Hollen said on Saturday citing an aid worker located on the frontline of the conflict in Syria.

As this aid worker's frontline report attests, Turkey is attacking Kurds outside the designated “zone”–a gross violation of the agreement, which the State Dept told me would trigger U.S. sanctions. Time to act! Inaction enables Erdogan’s ethnic cleansing. https://t.co/EyY1ZjTZRT — Chris Van Hollen (@ChrisVanHollen) October 26, 2019

The claim arrives following reports on Friday of renewed clashes between Kurdish and Turkish forces in northeast Syria, where a shaky cease-fire is in effect.

Russia and Turkey agreed on a plan on Tuesday to push Syrian Kurdish fighters from a wide swath of territory just south of Turkey’s border. The agreement will leave Turkey and Russia in control of territory formerly held by formerly U.S.-allied Kurdish forces, namely the People’s Protection Units (YPG).

Meanwhile, AFP reported on Saturday night that 15 dead so far on the day between Turkish forces and Kurds clashes.

#BREAKING 15 dead in Syria clashes between pro-Turkish forces, Kurds, according to monitor pic.twitter.com/Wvm7cIO6n1 — AFP news agency (@AFP) October 26, 2019

Ankara sees the YPG as a threat due to its links to Kurdish separatists on its soil and on Oct. 9 launched a military operation in northeast Syria targeting the group and aiming to create a safe zone. The offensive was halted on day nine, following a U.S.-brokered agreement to a temporary ceasefire.

The attack by Turkish forces against Kurds would trigger U.S. sanctions, Van Hollen said citing the U.S. state department.

"Time to act! Inaction enables Erdoğan’s ethnic cleansing,’’ the U.S. Senator wrote on Twitter.

The U.S. Congress has condemned Turkey’s military operation in northeast Syria, since the Kurdish forces targeted in the offensive have played a key role in the U.S.-backed fight against Islamic State (ISIS).

Three bills have been introduced to Congress recommending tough sanctions on Turkish institutions and officials including President Recep Tayyip Erdoğan.