International concerns have been raised by Pakistan's growing nuclear arsenal, while Beijing has faced much criticism for its co-operation over nuclear energy with Islamabad.
Pakistan's newly elected Prime Minister Nawaz Sharif, who turned the country nuclear in 1998, sought Chinese assistance in the field of civil nuclear technology to overcome the country's energy crisis during a meeting with visiting Premier Li Keqiang in Islamabad last month.
Indeed, there are indications that nuclear co-operation is now going to be the prime driver of the Sino-Pakistan strategic partnership. Sharif's government has reportedly decided to launch work on a 1.1 GW nuclear power plant in Karachi with Chinese assistance.
One aspect cannot be ignored: China has deepened co-operation largely in response to the civil nuclear energy deal signed between the US and India in 2008. That deal opened up a US$150 billion market for US nuclear trade with India, which was controversially granted an exemption from the Nuclear Suppliers Group.
Neither India nor Pakistan, arch-rivals in many aspects, have joined the nuclear Non-Proliferation Treaty, yet both possess nuclear arsenals. The US denied Pakistan a civilian nuclear deal, saying that it first had to improve its nuclear proliferation record.
So instead, the country has got what it needs from China.
Co-operation between China and Pakistan has so far focused largely on the Chashma nuclear power complex in Punjab.
Two plants, developed with Chinese support, are already in operation. Another two reactors, each with a capacity of 340 MW, are being built and the two nations agreed in March to construct a 1 GW plant at the complex, to help meet Pakistan's target of 8GW of nuclear power by 2025.
Pakistan's nuclear arsenal has been a sensitive topic for the US as it tries to improve relations with its frontline ally in the campaign against Islamist extremists. The US has restricted nuclear-related exports to Pakistan since it conducted its nuclear tests in 2008.
Beijing's nuclear co-operation with Islamabad is likely to stir international concerns over the security of nuclear materials in a country where extremists are challenging the state's writ.
Li's visit to Pakistan was aimed at deepening strategic bilateral ties, and nuclear co-operation is the essential part of the friendship package. Seven years ago, before the US had signed its civilian nuclear deal with India, Beijing shelved the project to build two more nuclear power plants in Pakistan as it succumbed to pressure from the West and the Nuclear Suppliers Group.
Today, the geopolitical landscape is very different.
Syed Fazl-e-Haider is a development analyst in Pakistan