The Taliban seized a province just south of Afghanistan's capital and launched a multi-pronged assault early Saturday on Mazar-e-Sharif, a major city in the north defended by powerful former warlords, Afghan officials said.

Homa Ahmadi, a lawmaker from Logar, says the Taliban control the entire province, including its capital, and reached a district in the neighbouring Kabul province on Saturday. That puts the insurgents less than 80 km (50 miles) south of the nation's capital.

The Taliban have also captured much of northern, western and southern Afghanistan less than three weeks before the United States is set to withdraw its last troops.

Munir Ahmad Farhad, a spokesman for the provincial governor in northern Balkh province, meanwhile said the Taliban attacked the city of Mazar-e-Sharif from several directions, setting off heavy fighting on its outskirts. There was no immediate word on casualties.

Afghan President Ashraf Ghani had flown to Mazar-e-Sharif on Wednesday to rally the city's defences, meeting with several militia commanders allied with the government.

The Taliban captured much of southern Afghanistan in recent days in a rapid offensive that has raised fears of a full takeover. Their lightning advance has left the Western-backed government in control of a smattering of provinces in the center and east, as well as Kabul and Mazar-e-Sharif.

The withdrawal of foreign forces and the swift retreat of Afghanistan's own troops despite hundreds of billions of dollars in US aid over the years has raised fears the Taliban could return to power or the country could be plunged into civil war.

The first Marines from a contingent of 3,000 arrived on Friday to help partially evacuate the US Embassy. The rest are set to arrive by Sunday, and their deployment has raised questions about whether the administration will meet its August 31 withdrawal deadline.

The Taliban meanwhile released a video in which an unnamed insurgent announced the takeover of the main radio station in the southern city of Kandahar, which fell to the insurgents earlier this week.

The station has been renamed the Voice of Sharia, or Islamic law. He said all employees were present and would broadcast news, political analysis and recitations of the Quran, the Islamic holy book. It appears the station will no longer play music.

It was not clear if the Taliban had purged the previous employees or allowed them to return to work. Most residents of Kandahar sport the traditional dress favored by the Taliban. The man in the video congratulated the people of Kandahar on the Taliban's victory.

The Taliban have operated mobile radio stations over the years, but have not operated a station inside a major city since they ruled the country from 1996-2001. At that time, they also ran a station called Voice of Sharia out of Kandahar, the birthplace of the militant group. Music was banned.

The US invaded shortly after the 9/11 attacks, which al-Qaida planned and carried out while being sheltered by Taliban. After rapidly ousting the Taliban, the US shifted toward nation-building, hoping to create a modern Afghan state after decades of war and unrest.

Earlier this year, President Joe Biden announced a timeline for the withdrawal of all US troops by the end of August, pledging to end America's longest war. His predecessor, President Donald Trump, had reached an agreement with the Taliban to pave the way for a US pullout.

Biden's announcement set the latest offensive in motion. The Taliban, who have long controlled large parts of the Afghan countryside, moved quickly to seize provincial capitals, border crossings and other key infrastructure. They are now within 80 km (50 miles) of Kabul.

Tens of thousands of Afghans have fled their homes, with many fearing a return to the Taliban's oppressive rule. The group had previously governed Afghanistan under a harsh version of Islamic law in which women were largely confined to the home.