By Bob Woodward and Don Oberdorfer Washington Post Staff Writers The United States and the Soviet Union have engaged in some unpub- licized tough talk during the past month over growing indications - . ficial described the message as ex- ’ tremely grave and said that Wash- - ington, in effect; told Moscow to that Pakistan’s nuclear program has moved far along the path toward production of an atomic bomb, ac- cording to administration sources. The discussion was generated by a direct and unusually. tough Soviet . warning to Pakistan about its nu- clear activities, the sources said, in- cluding a charge that the Pakistanis Apgroved F KPH are on the verge of constructing a nuclear bomb, which Moscow indi- cated it would not tolerate. The Reagan administration, on learning of the warning, responded with a private message to Moscow reiterating the strong U.S. commit- ment to Pakistan’s security. One of- keep “hands off” Pakistan. A well-placed intelligence source said that Central Intelligence Agen- cy analysis shows that Pakistan has or soon will have the capacity to build a bomb, despite official denials Tpeisonge by Pakistan. Sources said long- standing Pakistani nuclear efforts have increased this year. According to one account, it is just a matter of assembling components. The security of Pakistan as well as its highly secretive nuclear pro- gram are likely to be discussed dur- ing the visit of Pakistani Prime Min- _ ister Mohammad Khan Junejo, who - is to arrive late today on his first of- ficial visit to Washington. [Details — on Page A13]. Junejo, whose civilian govern- ment was installed last Dec. 30 af- See PAKISTAN, A13, Col. t 46966 AG01004 swe" -2 US., Soviets Spar Over Pakistan Bomb PAKISTAN, From Al ter nearly nine years of military rule, is to meet President Reagan Wednesday morning and see other senior administration figures as well as members of Congress be- fore departing Friday. Pakistan is particularly sensitive for both superpowers because of its geography bordering Afghanistan and because nearly all of the U.S. covert assistance to the Afghani- stan resistance fighting the Soviet army flows through Pakistan, with Pakistani permission. The Soviets have issued a num- ber of stern warnings to Pakistan to stop that flow in the past several years, and Soviet warplanes based in Afghanistan have repeatedly crossed the border into Pakistani airspace, bringing protests from Washington as well as isladgpqarovedeectb: el ats @: 2080 KaBI08 The immediate impetus for the recent Soviet warning to Pakistan is believed by Washington officials to have been the visit to Moscow in mid-June by Indian Foreign Minis- ter P. Shiv Shankar, who reportedly complained vociferously about Pak- istan’s nuclear efforts. Moscow’s warning, which was delivered by the Soviet ambassador in the Pakistani capital of Isla- mabad, also covered the Afghani- stan issues. It was considered par- ticularly important, though, be- cause of the nuclear aspect, which had not been a matter of urgency in other recent Moscow-Islamabad ex- . changes. Pakistan’s well-advanced nuclear program, which goes back well over a decade, is a touchy issue in Wash- ington. The Carter agiministrat won strongly condemned Pakistan and cut off U.S. aid to Pakistan be- cause of them. The Reagan - administration, which began a $3.2 billion Pakistan aid program in 1981, has been re- quired by Congress to certify an- nually that Pakistan does not “pos- sess” an atomic bomb. A stronger assurance may be required to per- suade Congress to approve a new $4 billion U.S. aid program nego- tiated with Pakistan this March. White House national security af- fairs adviser John M. Poindexter is concerned, according to sources, that the administration may not be able to certify to Congress. as re- quired in October that Pakistan does not “possess” a weapon. High- level meetings have reportedly been held in recent days to assess the Pakistani nuclear program in light of the most recent U.S. intel SS TAcRAPAR:QN789RQ001 istan] has the bomb or will soon,” a congressional source said. Leonard S. Spector, an expert on nuclear nonproliferation issues at. the Carnegie Endowment for Inter- national Peace, reported in Novem- ber that Pakistan is “at the thresh- old of becoming a nuclear-weapons state.” Spector said yesterday that more recent information, which he said he could not describe in detail, suggests that “something very se- rious has happened” in the Pakistani nuclear program since last winter. In March the Foreign Report of The Economist of London cited re- ports that Pakistan had succeeded in enriching uranium to 30 percent at its heavily guarded atomic plant ta. While this would be well short of the 90 percent level | needed to make a bomb, such an ’ achievement would far exceed the 5 percent level reportedly cited in a confidential letter from Reagan to Pakistani President Mohammed Zia ul-Haq in September 1984 as the highest enrichment level acceptable | GOWAGA Guedes |