China is moving ahead with plans to sell two nuclear reactors to Pakistan in a deal U.S. officials say will violate Beijing’s promises under an international nuclear control group.

The deal is raising new concerns in both the United States and India over continuing support from China to Pakistan’s nuclear weapons program, which benefits from the civilian reactor programs.

"China’s expanding civil nuclear cooperation with Pakistan raises serious concerns and we urge China to be more transparent regarding this cooperation," a State Department official said.

"We believe that the announced agreement for Chinese provision of new nuclear reactors to Pakistan extends beyond cooperation that was ‘grandfathered’ when China was approved for Nuclear Suppliers Group (NSG) membership in 2004," the official said.

The illicit reactor sale was discussed during recent meetings of the NSG and the United States will continue to do so in future session, the official said.

China on Wednesday made its first public comments on the Pakistani nuclear cooperation, telling reporters in Beijing that the civilian reactors will be built strictly according to international norms.

"Relevant cooperation is in strict accordance with the two countries' international responsibility and is for peaceful aims. We also receive the supervision of the International Atomic Energy Agency (IAEA)," Foreign Ministry spokeswoman Hua Chunying said.

The issue is expected to be raised when Indian Prime Minister Manmohan Singh visits Beijing next week, where he is expected to meet with Chinese President Xi Jinping.

Indian officials have lodged protests in Beijing opposing the reactor sale and telling Chinese officials that the reactors will have security consequences for India. Delhi also has protested the proposed sale with the Nuclear Suppliers Group, which last met in June.

According to U.S. officials and diplomatic sources, the state-run China National Nuclear Corp. (CNNC) has agreed to sell two 1,100-megawatt reactors to the Pakistan Atomic Energy Commission (PAEC) for $9.6 billion.

The covert nuclear deal has been in the works since February when Pakistani officials secretly held talks in Beijing with Chinese nuclear officials. An initial agreement was signed Feb. 18 between PAEC Chairman Ansar Parvez and Sun Qin, CNNC chairman.

Details of the Pakistan-China nuclear deal involving transfer of a single 1,000-megawatt reactor were first disclosed by the Free Beacon in March.

A Pakistani official confirmed to the Wall Street Journal this week that the deal now includes two reactors and that it was kept secret because "I fear dirty hands will start their spoiling work."

Initially reported as reactors to be built in Chashma, where other Chinese nuclear reactors were built in the past, the officials said the final location of the two reactors is near Karachi at Paradise Point, about 25 miles west of the Pakistani capital.

If completed over the next several years, the sale would violate China’s commitment to the Nuclear Suppliers Group, an informal group of 48 nations that agreed not to export equipment and goods that could be used to develop or build nuclear arms programs to any state that is not a signatory of the Nuclear Nonproliferation Treaty.

China was allowed to sell several reactors for Pakistan’s Chashma facility, including two reactors after it joined the NSG in 2004 after Beijing claims the Chashma reactors were permitted under an agreement reached prior to that date.

However, the new reactors at a different location are covered by NSG restrictions and the transfer in violation of those norms is expected to severely weaken the international arms non-proliferation group.

Pakistan is not an NPT signatory but has benefited from covert Chinese nuclear technology transfers since the early 1980s including nuclear bomb design know-how, according to U.S. officials.

Pakistan’s nuclear arsenal is said to include about 100 nuclear bombs and missile warheads.

Pakistan also was the origin of a major covert nuclear arms supplier group headed by scientist A.Q. Khan, considered the father of Pakistan’s nuclear bomb. The supplier group was uncovered and shut down during the early 2000s, but not until after it had supplied nuclear arms equipment and design data to Libya, Iran and North Korea.

The reactors for the Karachi facilities were described as ACP1000 commercial reactors, indigenously built based on French designs sold to China in the 1990s. China claims that the reactor designs did not violate intellectual property controls.

The Karachi reactor sale is widely viewed by security analysts as China’s attempt to back its ally Pakistan in response to rival India’s civilian nuclear agreement with the United States that was also made outside the Nuclear Suppliers Group. India is not a NPT signatory.

According to diplomatic sources, the secret reactor deal was considered an extremely sensitive matter within the Chinese government, which ordered all Chinese officials within its nuclear establishment and political cadres to keep the matter secrets.

In a related development, the sources said a large delegation of Chinese nuclear executives visited Pakistan in March.

The delegation included representatives from the China Zhongyuan Engineering Corp., Shanghai Nuclear Engineering Research and Design Institute, the CNNC Nuclear Power Operation Management Co. Lt, and the East China Electric Power Design Institute.

The visit coincided with a meeting of the managers for the Chashma Nuclear Power Plant Unit 3 and Unit 4 reactors to be built by the Chinese. The meeting included discussions of safety inspection, quality assurance, as well as pricing of the two near reactors.

In addition to the nuclear deal, China recently took control of a strategic port facility in the west coast Pakistani port of Gwadar, located close to oil shipping lanes from the Persian Gulf.

China is expected to use the Gwadar port as a refueling and rest stop for its naval forces.