There are fears for more than 60 Australians detained in a Syrian camp after a US withdrawal paved the way for attacks from Turkey.

US President Donald Trump said he would "totally destroy and obliterate" Turkey's economy if it took action in Syria that he considered "off limits" following his decision on Sunday to pull 50 American special forces troops from northeastern Syria.

But the withdrawal has left Kurdish-led forces in Syria that have long allied with the US vulnerable to a planned incursion by the Turkish military, which brands them terrorists.

Donald Trump's decision to withdraw US troops has been criticised even by fellow Republicans. (AP/AAP)

There are reports Turkish warplanes have already begun bombing Kurdish positions in Syria. The Syrian Democratic Forces have described the US withdrawal as a "stab in the back".

Foreign Minister Marise Payne has expressed concern for the Australian women and children but warns the government will not rush to evacuate them.

"We will not put Australian officials, forces or our public in danger so any repatriation will occur only if safe to do so," Senator Payne said.

The Al-Hawl camp in Syria holds more than 70,000 people, including more than 60 Australians. (AAP)

Marise Payne says the government will not risk lives to rescue the Australians in the camp. (AAP)

Senator Payne said the government was in close consultation with its allies about the development in Syria, including through its embassies and other officials.

"The Australian government urges restraint by all parties to the conflict in Syria, and calls for all to avoid escalatory actions that cause further instability and added risks of humanitarian suffering," she said.

Kamalle Dabboussy's daughter Mariam and her children - aged one, three and five - are stuck in the Syrian camp.

He fears they are at risk from Islamic State extremists inside the camp, sleeper cells beyond its fence lines, diseases and inadequate medical care.

"There is no grace or saving opportunity for these women in the camp except by the intervention of the Australian government," Mr Dabboussy told 3AW radio.

Opposition frontbencher Kristina Keneally has met people who have family members in the al-Hawl camp.

There are fears of a Turkish invasion in the disputed area. (PA/AAP)

A US-backed Syrian Manbij Military Council soldier passes a US position near the tense front line with Turkish-backed fighters,in Manbij, north Syria. (AAP)

"Some of these people are genuine victims," Senator Keneally told ABC radio today.

"What I would encourage is that the government continues to work with the families and with our national security agencies to consider if anything can be done to extract these children to safety."

Senator Keneally believes the looming US withdrawal makes the task far more urgent.

"The opportunity, the window if you will, to safely extract the children and indeed those people who are adults is coming to a close," she said.

"The decision by the Americans to withdraw concert could certainly be hastening that time frame."

Fighters of the Syrian Democratic Forces march during a demonstration against possible Turkish military operation in their areas in Al-Qahtaniya, Syria. (AP)

TRUMP'S THREATS TO TURKEY

The Trump administration's move to withdraw US forces runs counter to the positions of even some of the president's top allies in his own party.

"It is time for us to get out of these ridiculous Endless Wars, many of them tribal, and bring our soldiers home," Mr Trump tweeted.

"Turkey, Europe, Syria, Iran, Iraq, Russia and the Kurds will now have to figure the situation out."

However, Mr Trump later threatened to destroy the Turkish economy if Ankara takes steps which are "off limits."

"As I have stated strongly before, and just to reiterate, if Turkey does anything that I, in my great and unmatched wisdom, consider to be off limits, I will totally destroy and obliterate the Economy of Turkey (I've done before!)" Mr Trump posted on Twitter.

The Pentagon later clarified it was not endorsing a Turkish invasion.

JIHADI BRIDE STRIPPED OF CITIZENSHIP

Meanwhile, a notorious jihadi bride has been stripped of her Australian citizenship.

Zehra Duman, who fled Australia as a teenager to marry an Islamic State fighter, was notified of the government's decision in recent days.

Duman is a dual Turkish and Australian citizen.

There are concerns the decision could leave her children, aged one and three, stateless.

The government declined to comment on the case.

However, a spokeswoman said that in general terms, cancelling a parent's citizenship did not sever their child's ties to Australia.