Another earthquake has struck the border region of Turkey and Syria, just two weeks after the area was devastated by a larger quake which killed more than 47,000 people and damaged or destroyed hundreds of thousands of homes.

Today's quake, this time with a magnitude of 6.3, was centred near the southern Turkish city of Antakya and was felt in Syria, Egypt and Lebanon.

It struck at a depth of just 2km, the European Mediterranean Seismological Centre (EMSC) said, potentially magnifying its impact at ground level.

Earlier, US Secretary of State Antony Blinken told Turkey that the United States will help "for as long as it takes" after the deadly earthquakes two weeks ago, as Turkish authorities carried out wide-scale demolition of damaged buildings.

Washington has sent a search and rescue team to Turkey, along with medical supplies, concrete-breaking machinery and additional funding in humanitarian aid that also covers Syria.

Ties between the NATO allies have been strained over issues including Ankara's purchase of Russian missile defence systems in 2019, NATO expansion and US support for Kurdish fighters in northeast Syria who are considered terrorists by Ankara.

"The United States and Turkey do not agree on every issue but it is a partnership that has withstood ...challenges," Mr Blinken told a joint news conference with Foreign Minister Mevlut Cavusoglu in Ankara.

Total US humanitarian assistance to support the earthquake response in Turkey and Syria has reached $185 million, the US State Department has said.

Mr Cavusoglu said he and Mr Blinken discussed a planned $20 billion purchase of US F-16 warplanes, and that Turkey would like the US administration to send formal notification of the potential F-16s sale to Congress.

Rescue work has begun to wind down two weeks after the earthquakes which have killed more than 46,000 people in southern Turkey and northwest Syria.

Turkey's Disaster and Emergency Management Authority (AFAD) said that nearly 13,000 excavators, cranes, trucks and other industrial vehicles had been sent to the quake zone.

The death toll in Turkey had risen to 41,156, AFAD said, and it was expected to climb further, with some 385,000 apartments in the country known to have been destroyed or seriously damaged and many people still missing.

Earthquake destruction in the Turkish city of Antakya

An aerial view of fault line cracks on land in Kahramanmaras, Turkey following the powerful earthquakes

Among the survivors of the earthquakes are about 356,000 pregnant women who urgently need access to reproductive health services, the UN sexual and reproductive health agency (UNFPA) said at the weekend.

The women include 226,000 in Turkey and 130,000 in Syria, about 38,800 of whom will deliver in the next month.

It said many of the women are sheltering in camps or are living exposed to freezing temperatures and struggling to get food or clean water.

In Syria, already shattered by more than a decade of civil war, most deaths have been in the northwest. The area is controlled by insurgents at war with forces loyal to President Bashar al-Assad, complicating efforts to get aid to people.

Medical charity Médecins Sans Frontières (MSF) said a convoy of 14 of its trucks had entered northwestern Syria from Turkey yesterday to assist in earthquake rescue operations, as concerns grow over lack of access to the war-ravaged area.

The World Food Programme (WFP) has also been pressuring authorities in that region to stop blocking access for aid from Syrian government-controlled areas, as it seeks to help hundreds of thousands of people affected by the quakes.

As of this morning, 197 trucks loaded with UN humanitarian aid had entered northwest Syria through two border crossings, a spokesperson for the UN Office for the Coordination of Humanitarian Affairs said.

Since Wednesday, thousands of Syrian refugees in Turkey have returned to their homes in northwest Syria to get in touch with relatives affected by the devastation.

At the Turkish Cilvegozu border, hundreds of Syrians lined up starting early today to cross. Mustafa Hannan, who dropped off his pregnant wife and three-year-old son at 7.30am, said he saw about 350 people waiting.

The 27-year-old car electrician said his family were leaving for a few months after their home in Antakya collapsed, taking up a pledge by authorities allowing them to spend up to six months in Syria without losing the chance to return to Turkey.

"I'm worried they won't be allowed back," he said. "We’ve already been separated from our nation. Are we going to be separated from our families now too? If I rebuild here but they can’t return, my life will be lost."