Afghanistan would become a "pariah state" if the Taliban take control by force, US Secretary of State Antony Blinken said Wednesday, as a top-level delegation from the insurgent group visited China to assure officials of their international obligations.

"An Afghanistan that does not respect the rights of its people, an Afghanistan that commits atrocities against its own people would become a pariah state," Blinken told reporters in India, where he is on his first official visit.

In China, the Taliban's leadership assured Beijing the group will not allow Afghanistan to be used as a base for plotting against another country.

A delegation including co-founder Mullah Abdul Ghani Baradar is in China for talks as the insurgents continue a sweeping offensive across Afghanistan -- including areas along their shared border.

Afghan security force personnel searching a commuter at a checkpoint in Herat, western Afghanistan Afghan security force personnel searching a commuter at a checkpoint in Herat, western Afghanistan Photo: AFP / Hoshang Hashimi

Their frontier is just 76 kilometres (47 miles) long -- and at a rugged high altitude without a road crossing -- but Beijing fears Afghanistan could be used as a staging ground for Uyghur separatists in Xinjiang.

Taliban spokesman Mohammad Naeem told AFP those concerns were unfounded.

"The Islamic Emirate assured China that Afghanistan's soil would not be used against any country's security."

"They (China) promised not to interfere in Afghanistan's affairs, but instead help to solve problems and bring peace."

Beijing confirmed the thrust of the talks, which were led on the Chinese side by Foreign Minister Wang Yi.

Afghanistan's President Ashraf Ghani warned that his nation was facing an 'invasion that is unprecedented in the last 30 years' Afghanistan's President Ashraf Ghani warned that his nation was facing an 'invasion that is unprecedented in the last 30 years' Photo: AFP / SAJJAD HUSSAIN

But in Kabul Afghanistan's President Ashraf Ghani urged the international community "to review the narrative of the willingness of the Taliban and their supporters on embracing a political solution".

"In terms of scale, scope and timing, we are facing an invasion that is unprecedented in the last 30 years," he warned in a speech Wednesday.

"These are not the Taliban of the 20th century... but the manifestation of the nexus between transnational terrorist networks and transnational criminal organisations."

In New Delhi, Blinken warned the Taliban they would have to change if they wanted global acceptance.

"The Taliban says that it seeks international recognition, that it wants international support for Afghanistan. Presumably it wants its leaders to be able to travel freely in the world, sanctions lifted, etc," he said.

US Secretary of State Antony Blinken boards an aircraft as he departs for New Delhi, India and Kuwait. Blinken said Afghanistan would become a 'pariah state' if the Taliban take control by force US Secretary of State Antony Blinken boards an aircraft as he departs for New Delhi, India and Kuwait. Blinken said Afghanistan would become a 'pariah state' if the Taliban take control by force Photo: X90178 / JONATHAN ERNST

"The taking over of the country by force and abusing the rights of its people is not the path to achieve those objectives."

Analysts say China, whose stated foreign policy position is non-interference in other countries' issues, is queasy about the religiosity of the Taliban given their proximity to Muslim-majority Xinjiang.

But the meeting gifts legitimacy to an insurgent group craving international recognition -- and a potential diplomatic shield at the UN -- to match their military march across the nation.

"Wang Yi pointed out, the Afghan Taliban is a crucial military and political force in Afghanistan," foreign ministry spokesman Zhao Lijian told reporters in Beijing.

"China has throughout adhered to non-interference in Afghanistan's internal affairs... Afghanistan belongs to the Afghan people," he said, in stark contrast to the "failure of US policy towards Afghanistan".

Taliban officials have cranked up their international diplomacy, seeking global recognition for when they hope to return to power.

They have made sweeping advances across Afghanistan since May, when US-led foreign forces began their final withdrawal.

Beijing hosted a Taliban delegation in 2019, but back-door links with the insurgents existed before, through Pakistan.

Communist Party leaders in Beijing and the fundamentalist Taliban have little ideological common ground, but experts feel shared pragmatism could see mutual self-interest trump sensitive differences.

For Beijing, a stable and cooperative administration in Kabul would pave the way for an expansion of its Belt and Road Initiative into Afghanistan, while the Taliban would consider China a crucial source of economic support.

"By getting the Chinese on their side, the Chinese would be able to provide them with diplomatic cover at the Security Council," Australia-based Afghanistan expert Nishank Motwani told AFP.

"It is important to note... when other countries open up their doors and engage with the Taliban it undercuts the legitimacy of the Afghan government and presents the Taliban almost as a government in waiting."

Moscow, meanwhile, said it will bolster Tajikistan's military with arms and equipment amid a "deteriorating" situation in Afghanistan after the Taliban recently captured a border crossing with the Central Asian nation.