The Afghan Taliban's leader said on Saturday the insurgents will not call a ceasefire any time soon, even as a US envoy was heading to the region for a fresh round of peace talks.

In a rare and defiant message ahead of what would be the seventh round of recent negotiations, Taliban chief Haibatullah Akhundzada boasted foreign forces in Afghanistan are “condemned to defeat” — but said the insurgents would continue talks with the US.

The Taliban's fight “and resistance against the occupation is nearing the stage of success, Allah willing,” Akhundzada said in a message for Eidul Fitr, the upcoming festival at the end of the holy month of Ramazan.

The insurgents, believing they have major leverage on the military front, have rejected widespread calls for a ceasefire.

“No one should expect us to pour cold water on the heated battlefronts of jihad or forget our 40-year sacrifices before reaching our objectives,” said Akhundzada, who has led the militants since his predecessor Akhtar Mansour was killed in a 2016 US drone strike.

Last year, the Taliban observed a three-day ceasefire over Eid and many Afghans — exhausted by decades of war and violence — had pinned their hopes on another truce this year.

Afghan President Ashraf Ghani had proposed a nationwide ceasefire at the start of Ramazan early last month, but the Taliban rejected the offer.

In Washington, the State Department said Zalmay Khalilzad — the Afghan-born US diplomat tasked with trying to bring America's longest war to an end — on Friday left for a 17-day trip to Qatar, Afghanistan, Pakistan, Germany, Belgium and the United Arab Emirates.

Khalilzad took to Twitter to say he believes the peace process is progressing, even though the last round of talks ended with the two sides at apparent loggerheads over when the US might pull its troops from Afghanistan.

“We've made substantial progress over the last month. On this trip, I want to take that momentum and accelerate the #AfghanPeaceProcess”, he wrote.

Khalilzad added that he was optimistic about talks, and called for parties to show “flexibility”.

He will speak with the Taliban in the Qatari capital Doha, where the two sides have repeatedly met.

Peace walk

Despite some progress, with both sides believed to have agreed on various aspects of a proposed deal, violence between the Taliban and US-backed Afghan government forces has continued unabated.

A major sticking point remains the refusal of the Taliban to negotiate with Ghani's government, which enjoys international support.

Khalilzad will start his trip in Pakistan which has facilitated talks with the Taliban.

In Kabul, he will meet representatives of civil society and women's rights groups, which have been especially concerned about a future Afghanistan with the Taliban at the helm.

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In a sign of the Afghans' frustration with their country's seemingly unending conflict, a group of protestors have restarted a peace march that last year saw them walking across Afghanistan and into the capital Kabul.

Bismillah Watandost, a spokesman for the People's Peace Movement, told AFP on Saturday that about 30 people had started the walk late Thursday, heading from Lashkar Gah to Musa Qala in Helmand province, a Taliban stronghold.

“We will be marching 150 kilometres (93 miles). Some of our friends have blisters on their feet from wearing old shoes,” Watandost said.

“This is our first peace march during the holy month of Ramazan. All of us are fasting.” He said the group aims to express to the Taliban the pain and suffering of Afghans.

“Even if we are intimidated with death threats, we won't care about it,” Watandost said.

On Friday, former president Hamid Karzai mistakenly declared the Taliban had announced a new ceasefire after hearing an old message the insurgents had put out last year.

Karzai's announcement unleashed a brief spell of confusion across the country, with media outlets firing off tweets and breaking news reports announcing the alleged truce.