China, an all-weather ally of Pakistan, has been the main supplier of arms and defense equipment to Islamabad's ambitious military modernization programme.

The names of the companies are Xi’an Longde Technology Development, Tianjin Creative Source International Trade and Granpect Co. Ltd from China and Minsk Wheel Tractor Plant from Belarus.

These entities “have engaged in activities or transactions that have materially contributed to, or pose a risk of materially contributing to, the proliferation of weapons of mass destruction or their means of delivery, including any efforts to manufacture, acquire, possess, develop, transport, transfer or use such items, by Pakistan,” State Department spokesperson Matthew Miller said on Friday.

Miller said the US is committed to strengthening the global nonproliferation regime by taking action to disrupt procurement networks supporting proliferation activities of concern.

Reacting to media queries regarding the US sanctioning three Chinese companies and a company from Belarus, Pakistan’s Foreign Office spokesperson Mumtaz Zahra Baloch said: “We reject political use of export controls.

"It is well known that the same jurisdictions, which claim strict adherence to non-proliferation controls, have waived off licensing requirements for advanced military technologies for some countries,” Baloch said, apparently referring to the US allowing the export of sophisticated arms to countries like India.

“Such discriminatory approaches and double standards are undermining the credibility of non-proliferation regimes and also the objectives of regional and global peace and security by accentuating military asymmetries,” she said in Islamabad.

The Minsk Wheel Tractor Plant in Belarus supplied special vehicle chassis to Pakistan’s long-range ballistic missile programme.

Such chassis are used as launch support equipment for ballistic missiles by Pakistan's National Development Complex (NDC), which is responsible for the development of Missile Technology Control Regime Category (MTCR) I ballistic missiles, according to a State Department Factsheet.

China's Xi’an Longde Technology Development Company Limited, supplied missile-related equipment, including a filament winding machine, to Pakistan’s long-range ballistic missile programme that the US said was destined for Pakistan's NDC.

Filament winding machines can be used to produce rocket motor cases.

Tianjin Creative Source International Trade Co Ltd supplied missile-related equipment to Pakistan’s long-range ballistic missile programme, including stir welding equipment (which the United States assesses can be used to manufacture propellant tanks used in space launch vehicles), and a linear accelerator system (which the United States assesses can be used in the inspection of solid rocket motors).

Tianjin Creative’s procurements were likely destined for Pakistan’s Space and Upper Atmosphere Research Commission (SUPARCO), which develops and produces Pakistan’s MTCR Category I ballistic missiles, the US state department said.

Granpect Company worked with Pakistan's SUPARCO to supply equipment for testing large-diameter rocket motors.

In addition, Granpect Co. Ltd. also worked to supply equipment for testing large-diameter rocket motors to Pakistan’s NDC.