NEW YORK, April 9: American prosecutors disclosed on Friday that an Israeli national working in South Africa had pleaded guilty of arranging illegal exports of American-made nuclear equipment to India, Pakistan and other countries, the New York Times said on Saturday.

Asher Karni, an Israeli national who lives in South Africa, entered the guilty plea last September and had been cooperating with investigators, US prosecutors said.

The prosecutors, however, kept the proceeding secret until Friday, when they unsealed the plea agreement and charges brought against Humayun Khan, an Islamabad businessman with longstanding ties to Pakistan’s military. Mr Khan is said to be Mr Karni’s partner, according to the paper.

As part of Mr Karni’s plea agreement, he acknowledged that he Was also involved in 2002 in selling sophisticated electronic equipment to government agencies in India, some of which are involved in nuclear weapons and missile research. It is not clear whether the goods he sold were useful for making nuclear weapons.

The indictment of Mr Khan states that he employed Mr Karni in 2002 and 2003 to buy 200 high-speed electrical switches that can be used in a nuclear device, as well as oscilloscopes, and to export them to Pakistan without the required United States export licenses. The switches, known as triggered spark gaps, are used in medical equipment but also have military applications, including as detonators for nuclear weapons, the prosecutors said.

Mr Khan is believed to be in Pakistan and a Pakistani embassy official said he was unaware of an American request to have him detained. Efforts to reach Mr Khan were unsuccessful, the paper said.

Mohammad Sadiq, the deputy chief of mission at the Pakistani embassy in Washington, denied that Humayun Khan was involved in procuring triggers or other equipment.

A senior Commerce Department official said on Friday that, with Mr Karni’s help, the investigation had turned up indications that Mr Khan was involved in sales of nuclear-related technology to countries other than Pakistan, using a network of suppliers and middlemen similar to that used by Pakistani nuclear scientist A.Q. Khan.

The two Khans were not believed to be related, officials said. “Humayun Khan is a black marketeer involved in the proliferation of nuclear weapons, and once this is all spelled out we’re going to see the same scale of network that A.Q. Khan was involved in,” said the Commerce Department official.

Karni was arrested in Denver in 2004 after travelling to the United States with his family for a vacation.

He ran a company called Top-Cape Technology from Cape Town, South Africa.