The International Committee of the Red Cross said on Friday it was "deeply alarmed" by the situation in Syria's Aleppo province, where fighting has displaced tens of thousands of people.

The statement came as rights group Amnesty International criticised Turkey for refusing entry to some injured Syrian civilians fleeing Aleppo, describing its policy as "appalling".

The ICRC said it was "deeply alarmed by the situation in the Aleppo region, where fighting is intensifying, hospitals and health workers have been targeted, people have no water or electricity and more than 70,000 have now fled their homes".

"The most basic infrastructure to support the lives of the people has been critically damaged, worsening the situation of the population dramatically, with the number of newly displaced people rising by the day," ICRC Syria delegation head Marianne Gasser said.

The comments come after a major operation by government forces backed by Russian air power that has seen the regime recapture territory north of Aleppo city.

The advances have left rebels and some 300,000 civilians virtually encircled in the opposition-held east of Aleppo city, and prompted tens of thousands of people to flee the countryside north of the city.

Simultaneously, Kurdish-led forces have advanced against rebels further north in the province, prompting Turkish shelling and further complicating the volatile situation there.

The ICRC urged all parties to the conflict to avoid attacks on medical facilities and civilian infrastructure including water treatment plants.

Amnesty International meanwhile criticised Turkey, saying it had denied entry to injured Syrians fleeing Aleppo in need of urgent medical care.

It said Turkish security forces had also shot and wounded Syrian civilians who had "out of desperation" tried to cross the border illegally with the help of smugglers.

The group was concerned about "civilians who remain trapped between daily airstrikes and dire humanitarian conditions", said Crisis Response Director Tirana Hassan.

"Turkey's highly selective practice is appalling -- only severely injured people are allowed entry to seek medical treatment while everyone else fleeing the violence is left unprotected," Hassan added.

Amnesty urged Turkey to keep its borders open, and called on the international community to increase support to Turkey and other countries neighbouring Syria that have taken in refugees.

More than four million Syrians have fled their country's conflict, and Ankara says it is hosting more then 2.6 million of them.