Kazakh Leader Vows to Ratify Arms Proliferation Pact : Nuclear weapons: He makes pledge to U.S. secretary of state. Clinton may visit early next year.

Bearing promises of aid and a visit with Bill Clinton, Secretary of State Warren Christopher won a pledge from Kazakhstan’s president Sunday to secure ratification of the Nuclear Non-Proliferation Treaty by the end of the year.

The move means that Kazakhstan is likely to renounce nuclear weaponry once Soviet-era missiles and bombers are removed from its territory.

But Christopher faces a tougher test today: a meeting with the president of Ukraine, who has suggested that he wants to cut a separate deal over some of the roughly 1,800 nuclear warheads his country inherited from the Soviet Union.

The Kazakh president, Nursultan Nazarbayev, surprised U.S. officials with the pledge, which he offered in exchange for a promise of a meeting with President Clinton, probably early next year.

In addition, Christopher announced a package of up to $140 million in aid for Kazakhstan for the new fiscal year that began this month, about triple the amount offered last year.

Aides to Christopher said Nazarbayev’s action is important for two reasons: It is the first time the Kazakh leader has publicly promised to join the treaty by a specific date, and it will help the secretary of state put more pressure on Ukraine to dismantle its missiles.

Ukraine’s arms stocks put it behind only the United States and Russia as a nuclear power. Ukrainian President Leonid Kravchuk has repeatedly promised to dismantle the arsenal, only to delay the pledge in the face of demands from nationalist groups.

Christopher flew to Kiev, the Ukrainian capital, Sunday night to urge Kravchuk to give up the nuclear weapons, but an aide said: “We are not very optimistic.”

Kravchuk told reporters in Kiev last week that he does not believe the existing agreements on nuclear weapons require him to destroy all of Ukraine’s missiles.

U.S. officials were dismayed by the statement.

The Administration is concerned that Ukraine’s government is gradually taking over command and control of the nuclear weapons on its territory, supplanting Russia’s role, a senior U.S. official said.

Christopher is visiting all four countries that inherited Soviet nuclear weapons--Russia, Ukraine, Kazakhstan and Belarus--with the aim of keeping their disarmament plans on track.

Ukraine, Kazakhstan and Belarus promised last year to either dismantle their nuclear weapons or ship them to Russia for dismantling there, but so far only Belarus has taken significant steps toward disarmament.

In Kazakhstan, the vast Central Asian republic where the Soviet military based its largest intercontinental nuclear missiles, Christopher and his aides said they were pleased with Nazarbayev’s renewed promises--although none of the missiles has been dismantled yet.

“We believe the non-proliferation treaty that has been enforced for more than a quarter of a century is one of the world’s most important agreements,” Christopher said.

The Nuclear Non-Proliferation Treaty, concluded in 1968 and ratified by more than 100 countries, prohibits non-nuclear countries from acquiring nuclear weapons.

Clinton will be in Moscow in January for a summit with Russian President Boris N. Yeltsin, and State Department officials said he could extend the trip for a visit to Kazakhstan--although they were unsure whether Alma-Ata, a tree-shaded provincial city with a handful of decrepit Soviet-era hotels, was ready for the burden of the traveling White House with its hundreds of attendant aides and reporters.

The promised U.S. aid includes a major program to help private enterprise develop in the republic, whose economy is dominated by oil, mining and cotton farming. It also features a $15-million fund to “rehabilitate” the Aral Sea, once the world’s fourth-largest inland sea, so overused for irrigation that it has shrunk by about one-third.

U.S. officials consider Kazakhstan a model for other new Central Asian republics in how to begin converting a Soviet state-run economy to private enterprise.

“This country has done everything right to attract private trade and investment,” said one.

Nazarbayev pressed his desire for help with his new country’s military security and at one point spread a map out on a table to point out to Christopher that Kazakhstan is surrounded by big powers--Russia to the north, China to the east and Iran off to the south.

The Kazakh leader has become an enthusiastic player of the old-fashioned diplomatic balancing act, playing one ally off against another.

He noted pointedly Sunday that he had just returned from a trip to China and said he hoped to establish “strategic relationships” with all his neighbors.

Christopher was given an in-your-face lesson in Central Asia’s geographic realities as he drove to the airport Sunday afternoon. The streets of Alma-Ata were lined with fluttering red, white and green Iranian flags, and the airport sported a welcome banner for the benefit of Nazarbayev’s next guest, arriving within an hour: Iranian President Hashemi Rafsanjani.