The United States is imposing sanctions on seven Pakistani companies for alleged links to the nuclear trade.

The Commerce Department's Bureau of Industry and Security (BIC) placed 23 companies —15 from Sudan and one from Singapore, in addition to the seven from Pakistan — on its Entity List.

The Entity List contains companies the U.S. determines are "acting contrary to the national security or foreign policy interests of the United States," according to BIC's website. Companies placed on the list need special licenses to do business in the United States.

A U.S. State Department spokesperson told VOA that the U.S. regularly adds entities to the list.

"It is not country-specific. Entities are looked at on a case-by-case basis, irrespective of national affiliation, and are added based on whether they operate counter to U.S. national security interests," the spokesperson said.

VOA tried to talk to some of the companies on the list, but they would not comment on their designation.

Pakistan said it would "seek more information" from the U.S. and these companies to better understand the circumstances which led to its listing.

A statement released by Pakistan's Ministry of Foreign Affairs said, "Pakistan believes that there should be no undue restrictions on the access to dual-use items and technologies for peaceful and legitimate purposes. Pakistan has always been transparent and willing to engage with the suppliers of the dual-use items."

Dual-use technologies have both civilian and possible military uses.

The sanctions could potentially hurt Pakistan's chances to join the 48-member Nuclear Suppliers Group (NSG). Pakistan wants to join the 48 countries who are members of the NSG, but the United States and some of its European allies oppose the move.

The NSG is dedicated to curbing nuclear arms proliferation by controlling the export and re-transfer of materials that could foster nuclear weapons development.

Nuclear-armed Pakistan applied to join the NSG in 2016, but has made little progress. The U.S. has been concerned about Pakistan's development of new nuclear weapons systems, including small tactical nuclear weapons, and has been trying to persuade Islamabad to make a unilateral declaration of "restraint."

Pakistani denials

Pakistani officials have been accused of handing over nuclear secrets to North Korea. The government has denied the accusations, though Pakistan has a poor record on nuclear proliferation.

Pakistan's Foreign Office said the nation's "efforts in the area of export controls and nonproliferation, as well as nuclear safety and security, are well known. Pakistan and the U.S. have a history of cooperation in these areas."

The announcement of sanctions has come as relations between Pakistan and the United States are at a low point. The United States accuses Pakistan of helping militant groups that attack the U.S. and its allied forces across the border in Afghanistan — a claim Pakistan denies.