The telephone lines between South Block and the US State Department have been burning hot ever since India launched coercive diplomacy against Pakistan in the aftermath of the December 13 terrorist attack on Parliament. So External Affairs Minister Yashwant Sinha was not surprised when his US counterpart Colin Powell called him at 9.40 p.m. on October 17. The topic for discussion was Pakistan but for once the focus was not India-Pakistan relations or Kashmir. It was the emerging nuclear nexus between India's neighbour and a prominent member of what US President George W. Bush calls the "axis of evil"- North Korea.

ON THE SLY: Musharraf claims Pakistan has not sold nuclear knowhow to North Korea; (right) Kim Jong II's country now has a bomb

Sources reveal that Powell and Sinha shared their serious concerns over the barter arrangement between Islamabad and Pyongyang, in which Pakistan had secretly supplied sensitive nuclear technology in return for missile technology from North Korea. The deal came to light after Korean officials admitted to a nuclear weapons programme during a meeting with US envoy James Kelly on October 4. A day after his talk with Sinha, Powell read the riot act to Pakistan President Pervez Musharraf on Islamabad's subterfuge. In an interview to an American TV channel, Powell said, "I had a very specific conversation with Musharraf on Friday where he assured us-400 per cent, he said-that Pakistan was not involved in nuclear proliferation. I have a relationship with President Musharraf that I believe he understands the consequences of such behaviour, and I take his word for it."

CAUGHT: The North Korean ship that was ferrying missile components to Pakistan

The diplomatic community in the US see this as an overt sign of Washington's pressure on Pakistan. Under the veiled threat of sanctions and non-proliferation laws, the US would now seek greater control over Pakistan's nuclear programme. In case of North Korea, the US has adopted a more restrained approach. This is evident from the fact that America shipped heavy fuel oil for nuclear reactors in North Korea even after Pyongyang's confession this month.

For Delhi, the revelation that Pakistan was clandestinely acquiring weapons of mass destruction from North Korea comes with a feeling of deja vu. At the peak of the Kargil War in 1999, Indian customs officials seized a North Korean ship Ku Wol San at Kandla which was carrying 170 tonnes of metal casings and missile components from Pyongyang to Karachi. It is now evident that North Korea also sold missile technology to Syria and Libya. The consignment included 22 technical instruction manuals in Korean language that have given India a deep insight into Pyongyang's missile prowess and Pakistan's missile capabilities.

BUILDING DISTRUST: The US is helping North Korea build this reactor for nuclear energy

The catch was instrumental in establishing "back channel" contacts between Delhi and Washington at the time when bilateral ties were lying in deep freeze due to Pokhran II in 1998. To date Delhi has studiously kept these "contacts" away from the prying eyes of intelligence agencies.

K. Santhanam, director, Institute for Defence Studies and Analyses, Delhi, says that India has known about the North Korea-Pakistan nexus since Pakistani nuclear scientist A.Q. Khan brought 10-12 Nodong missiles from Pyongyang between 1992 and 1994. The Pakistani 1,500-km range Ghauri (Hatf V) missile is an avatar of the Korean Nodong nuclear-payload delivery system. The missile for nuclear technology agreement was apparently sealed during the then prime minister Benazir Bhutto's quiet visit to Pyongyang via Beijing in December 1993.

It is apparent that Pakistan started looking at North Korea for missile technology after China signed a pact with the US in April 1984 against arms trade. Pyongyang also signed a pact with Washington in 1994, under which North Korea was to cap its nuclear weapons programme in return for US cooperation in production of nuclear energy. Clearly, the two pacts have been hit hard with the evidence that China, Russia and Pakistan helped North Korea in its uranium enrichment programme. Russia, on its part, denies it has anything to do with Pyongyang's quest for a nuclear bomb.

Although India has asked for an investigation into the Islamabad-Pyongyang nuclear nexus, it is clear the North Korean nuclear programme has the Pakistani stamp on it. This is evident from the fact that North Korea abandoned its pursuit of a plutonium-based bomb in the early 1990s and followed the Pakistani route of acquiring a weapon through the uranium enrichment process. Western intelligence reports say Pakistan supplied gas centrifuges-used in uranium enrichment-and key nuclear weapons technology to North Korea. "It occurred to us that there might be a complementarity of interest between North Korea and Pakistan," says Robert Einhorn, former US assistant secretary of state for nuclear non-proliferation. Santhanam believes that a Pakistani airline, run by a retired air force officer having close links with the ISI, was used to ferry the nuclear technology from Islamabad to Pyongyang.

With the bomb now tumbling out of the closet, the US is putting pressure on China to use its influence with its "all-weather friend" in Islamabad to stop nuclear proliferation and on North Korea for a roll-back of its nuclear programme. The nuclear issue topped the agenda of Chinese President Ziang Zemin during his trip to the US last week. It seems the US will use Chinese leverage to curtail the North Korean nuke programme just as it used Pakistani influence on the Taliban in Afghanistan last year. And as in the case of the Taliban, Washington cannot resolve the problem by simply talking.

-with Anil Padmanabhan in New York