UN chief Antonio Guterres has warned that any country supporting terrorism will ultimately have to pay a "high price" and offered his good offices to promote cooperation between Pakistan and Afghanistan to jointly fight the menace.

The Secretary-General arrived in Kabul on Wednesday and held bilateral meetings with Afghan President Ashraf Ghani and the country's Chief Executive Officer Abdullah Abdullah.

Later addressing reporters, the UN chief was asked about documents and proofs submitted by the Afghan government regarding involvement of Pakistan in "equipping and funding" terrorism and whether those documents had been considered by the world body.

"Those are areas of competence of the Security Council of the United Nations. What I am supposed to do as Secretary General is to use my good offices to promote the cooperation between the two countries for them to be able to fight together the threat of terrorism," Guterres said.

He noted that Ghani and Pakistan Prime Minister Nawaz Sharif had met in Astana on the sidelines of the Shanghai Cooperation Organisation (SCO) summit.

Source: b''

Guterres said he too had met Prime Minister Sharif in the Kazakh capital and his "objective is to do everything that is possible to facilitate and promote the cooperation of the two countries in addressing together the threat of terrorism".

"That is important not only for the two countries but for the whole world. We have seen horrible terrorist attacks in Afghanistan, like the last ones in Kabul, horrible terrorist attacks in Pakistan and attacks around the world. It is time to unite against terrorism and that is my objective as Secretary-General of the United Nations," Guterres added.

The UN chief was also asked about a number of countries in the region, particularly "Iran and China", which are beginning to support insurgent groups.

Guterres strongly rejected such claims saying, "I do not subscribe to the accusations."

He, however, added that his message to "any country that supports terrorism anywhere in the world is that this is the wrong thing to do and if any country supports terrorism one day in relation to other countries, sooner or later the price paid will be high in relations to terrorism within the country itself."