Longtime allies Pakistan and China on Monday vowed to enhance economic cooperation, expand trade, and encourage greater investments from Beijing.

According to Yeni Safak, in a phone call, Pakistan's Prime Minister Shehbaz Sharif, and his Chinese counterpart Li Keqiang agreed that an "All-Weather Strategic Cooperative Partnership" must continue to serve the vital interests of the peoples of the two countries, as well as the broader interests of peace and stability amid the evolving regional and global milieu.

The conversation between the two leaders followed a brazen suicide attack in Pakistan's commercial capital Karachi late last month, which killed three Chinese nationals among four.

Sharif, according to a statement from the prime minister's office, offered his condolences to China and expressed sympathies with the families of victims of the "heinous" terrorist attack that took place at the University of Karachi on April 26.

"The Prime Minister (Sharif) strongly condemned the terrorist attack and reaffirmed Pakistan’s firm resolve to hold a thorough investigation, to apprehend the perpetrators of this criminal act and to bring them to justice in accordance with our laws," the statement added.

Sharif thanked Beijing for its "firm" support to Pakistan’s sovereignty, territorial integrity, and national development and reaffirmed his government’s unwavering support to China on all issues of its core interest.

He reaffirmed his government’s firm resolve to fast-track both the ongoing as well as the new projects under the multi-billion-dollar China-Pakistan Economic Corridor (CPEC) project.

The $64 billion CPEC, signed in 2015, aims to connect China's strategically important northwestern Xinjiang province to the Gwadar port in southern Pakistan, through a network of roads, railways, and pipelines to transport cargo, oil, and gas.

While emphasizing people-to-people contacts, Sharif also conveyed sentiments of the families of the Pakistani students who are desirous of returning to China for resumption of their studies.

Thousands of Pakistani students who had returned after the coronavirus outbreak, have been struggling to get visas to resume their studies in different Chinese universities.

According to a readout from Beijing, Li told his Pakistani counterpart that China "prioritizes its ties with Pakistan in its international diplomacy."

He urged Pakistan to take all-out measures to apprehend the perpetrators of the Karachi attack and “to take more robust measures to ensure the safety of Chinese personnel and institutions in Pakistan,” according to China’s state broadcaster CGTN.

"China and Pakistan are close neighbors and 'iron-clad' friends," Li said.