Action against the Taliban will be part of the agenda during the fifth round of Afghanistan peace talks that will take place in Pakistan on Wednesday, high-level Afghan sources say.

The Taliban has repeatedly refused to take part in the negotiations and shows no signs of easing its ongoing spring offensive against the Afghan government.

Speaking to Al Jazeera on Tuesday from Islamabad, Omar Zakhilwal, the Afghan ambassador to Pakistan who is also heading the delegation, said: "The talks are no longer aimed at reviving negotiations with the Taliban.

"We have gone past that now. We are talking about serious steps that need to be taken against the Taliban. They refuse to come to a peaceful negotiation, so we need to discuss actions needed based on that.

"Despite that, peace still remains our preferred option."

The Taliban has not taken part in any of the four rounds of peace talks organised by the Quadrilateral Coordination Group (QCG) which comprises representatives from Afghanistan, Pakistan, China and the US.

"The Taliban are using their conditions as an excuse to continue violence," Zakhilwal said.

Reponding to Zakhilwal's comments, Zabihullah Mujahid, a Taliban spokesperson, told Al Jazeera the group would not budge from its demands.

"They [Afghan government] have been giving out such statements for very long now and it doesn't scare us," Mujahid said.

"Our conditions are still the same. We demand the implementation of Islamic law in Afghanistan and the departure of all foreign forces."

Pakistani perspective

Mohammad Nafees Zakaria, spokesperson for Pakistan's foreign affairs ministry, said the Islamabad meeting is aimed at resolving the ongoing conflict, the effect it has on Pakistan and the implementation of the plan prepared in the previous meetings.

"When we talk of peace, we are not talking about conditions, we are talking about requirements," he said.

"In the past, we've invited the Taliban to talk about the requirements for peace and stability in Afghanistan but they've always refused.

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"Pakistan is the most affected country due to the conflict and that's why we're committed to fighting terrorism and making every possible effort to bring peace."

Afghanistan has long accused Pakistan of actively harbouring the Taliban leadership.

"Pakistan still remains a venue and ground for gatherings from which mercenaries send us messages of war," Afghanistan President Ashraf Ghani said after an attack in Kabul last year.

In an unusually candid admission, Sartaj Aziz, adviser to the Pakistani prime minister on foreign affairs, admitted earlier this year that his country has considerable influence over the Taliban because its leaders live in Pakistan.

"We have some influence over them because their leadership is in Pakistan and they get some medical facilities," Aziz said in March.

"Their families are here. We can use that to pressurise them to 'come to the table'. But we can't negotiate on behalf of the Afghan government because we cannot offer them what the Afghan government can offer them."

Pakistan hosted the first round of direct talks between the Taliban and Afghanistan last year.

But the negotiations were abruptly halted after it was revealed that Taliban leader Mullah Omar had been dead for two years, a disclosure which prompted infighting in Taliban ranks.

Follow Shereena Qazi on Twitter @shereenaqazi