Turkish-backed Syrian rebels in Akcakale in Turkey’s Sanliurfa Province, across the border from Kurdish-controlled territory (Khalil Ashawi/ Reuters)

About 100,000 civilians have fled their homes amid Turkish attacks on mainly-Kurdish areas in northeast Syria, according to the UN.

Aid officials spoke of “yet another humanitarian crisis”, with “disturbing reports” of strikes on infrastructure such as water facilities, power stations, and oil fields.

Rupert Colville, the spokesman for the UN human rights office, said at least seven civilians, including a woman and a boy, have been killed since the Turkish cross-border offensive began on Wednesday.

He said 400,000 people in the city of Hasakeh risk losing access to clean water after a Turkish raid on a pumping station in the border town of Ras al-Ain.

Médecins Sans Frontières‎ announced the closure of a hospital that served more than 200,000 people in the town of Tel Abyad.

The heaviest Turkish attacks have been in or near Ras al-Ain and Tel Abyad. The Kurdish-led, US-supported Syrian Democratic Forces have responded with rocket and mortar fire into Turkish border towns.

The Turkish military declared that it has killed 399 “terrorists” since Wednesday. Officials claimed an 8-km (5-mile) advance into Syrian territory, capturing 14 villages.

The State agency Anadolu said 10 civilians were killed by SDF mortar attacks on Friday, eight in the town of Nusaybin and two in the town of Suruc.

Map: Al Jazeera

Erdoğan: “We Will Never Stop”

Facing UN statements and international criticism over the “humanitarian crisis”, Turkish President Recep Tayyip Erdoğan maintained his defiance, a day after threatening to send 3.6 million Syrian refugees to Europe.

Syria Daily, Oct 11: Turkey’s Erdoğan to World — We’re Not Stopping Our Attacks

“We will never stop this step. We will not stop no matter what anyone says,” he said.

Erdoğan has declared a “safe zone” of 480 km (270 miles) along the Turkish-Syrian border, extending east of the Euphrates River to Iraq, and 30 km (19 miles) deep for resettlement of the Syrian refugees. He said Thursday that 1 million Syrian refugees will be resettled there.

Ankara is targeting the Kurdish militia YPG, which it considers to be part of the Turkish Kurdish insurgency PKK. But the YPG is the largest element in the Syrian Democratic Forces, created by the US in October 2015 to remove the Islamic State from northeast Syria.

American officials continued on Friday to try and reclaim political ground after Donald Trump, in a Sunday phone call with Erdoğan, accepted the Turkish offensive and ordered US forces to pull back from the “safe zone”.

Treasury Secretary Steven Mnuchin said the Trump Administration was prepared to impose sanctions on Turkey. Defence Secretary Mark Esper told Turkish counterpart Hulusi Akar in a phone call to halt the offensive or risk “serious consequences”.

But a US official said “we have not seen significant examples so far” of Turkish actions that would trigger sanctions such as “ethnic cleansing” or “indiscriminate artillery, air and other fire directed at the civilian population”.

The Pentagon said US troops near the city Kobani came under artillery fire from Turkish positions on Friday night, with an explosion a few hundred meters from their position. There were no casualties.

The Turkish military said it was taking “all precautions…to prevent any harm to the US base….We ceased fire upon receiving information from the US”.

SDF: We Are No Longer Responsible for ISIS Fighters and Families

The Syrian Democratic Forces said on Friday that they are no longer responsible for guarding about 90,000 Islamic State fighters and families. Spokesman Mustafa Bali said, from the city of Hasakah:

We are currently subject to a genocidal attack. There is a project to make a demographic change and eradicate Kurds. Therefore, our first duty is the protection of our people, border and soil. All our forces are focusing on this now.

Our prisons…are like detonated bombs. We do not know when they will explode. However, this is no longer our responsibility.

Kurdish media declared that five ISIS fighters had escaped from a prison after nearby Turkish shelling.

About 74,000 of the Islamic State members and their relatives are in the al-Hol camp, outside the “safe zone”, but the SDF says that it has already drawn down the number of guards, as fighters are moved to the frontline.

Kurdish outlets claimed that almost 100 women had tried to escape al-Hol on Friday by attacking guards.

Four people were killed and nine injured on Friday in Qamishli by a bombing in which ISIS is suspected of responsibility.