Russia Offers Ukraine Its Nuclear Protection : Arms: The guarantee makes Kiev more likely to follow through on transferring its remaining atomic weapons to the Kremlin.

President Boris N. Yeltsin swept away a major obstacle to strategic disarmament, announcing Friday that Russia has agreed to place Ukraine under the protection of its atomic umbrella.

“Russia guarantees it will maintain and safeguard Ukraine’s integrity and protect its borders from a possible nuclear attack,” Yeltsin said.

Ukrainian President Leonid Kravchuk said Moscow’s pledge to guard his country’s “security, sovereignty and territorial integrity” with Russian ICBMs means Ukraine’s legislature should finally give its long-awaited formal consent to renouncing the nuclear arms on its territory.

“Ukraine has designated its political line, and is not getting ready to alter it,” Kravchuk said.

Because of the daisy-chain nature of nuclear disarmament accords, the deal struck by the presidents during negotiations at the Kremlin--which also produced important results on oil supplies for Ukraine and payment of the Soviet debt--has major implications for American diplomacy and security.

That is because Ukraine, as one of four former Soviet republics with nuclear weapons based on its territory, must formally ratify the 1991 U.S.-Soviet Strategic Arms Reduction Talks treaty, or START I, for it to take effect. In addition, the START II treaty signed by Yeltsin and President Bush on Jan. 3, which would slash U.S. and Russian strategic arsenals to a third of their current size by the year 2003, will become void unless the earlier pact is enacted.

The Ukrainians, whose country now contains the world’s third-largest nuclear force, have been demanding security guarantees from Washington and Moscow before allowing removal of the 1,656 warheads. Ukrainian envoys came home a week ago from Washington claiming to have secured some sort of a U.S. commitment in writing.

The Ukrainians say that blowing up missile silos amid fertile farmland and destroying poisonous liquid missile fuel will cost $1.5 billion; they want more than the $175 million offered by the U.S. government. They have even asked Yeltsin’s government to pitch in.

On this point, the Russians, whose economy is hardly in better shape than Ukraine’s, gave no firm commitment Friday but left the door open. Yeltsin said he and Kravchuk agreed that an additional “special agreement” on how to dismantle the 176 ICBMs now in Ukraine and destroy their thermonuclear warheads is needed.

A communique issued later said the countries would study how to reprocess the enriched uranium in nuclear warheads for use as fuel in Ukraine’s power plants--a substance Ukraine now must pay Russia hard cash for.

In their brief remarks to reporters, the presidents left some important questions unanswered. Perhaps most tantalizingly, Kravchuk eluded the issue of exactly when Ukraine’s legislature will ratify START I and the Nuclear Non-Proliferation Treaty, a delay that has irked both Russia and the United States.

In the communique, the leaders specified that the Russian nuclear umbrella will be extended only after ratification occurs. At the moment, Yeltsin has ultimate control anyway of the Soviet-built strategic forces in Ukraine, as well as those in Kazakhstan, Belarus and his own country.

But the terms of Friday’s agreement will now allow Kravchuk to return home and show his country that he got something--security pledges and a potential source of power plant fuel--for Kiev’s promise to renounce nuclear weapons and that it was not a giveaway as some Ukrainians charge.

Slavic cousins bound by 1,000 years of common history and seven decades of Communist rule, Russia and Ukraine have had a troubled, bickering and suspicion-ridden relationship since the collapse of the Soviet Union 13 months ago. To mark the turning of a new page, Yeltsin and Kravchuk held an elaborate document-signing ceremony Friday in the same lofty-domed Kremlin chamber where Bush and Yeltsin signed START II earlier this month.

“The chief political achievement is that we have remained friends,” Yeltsin told correspondents who came to St. Vladimir’s Hall. “Today we could have parted ways. But we didn’t.”

For the Ukrainians, it was not START I, but oil, that was their chief immediate concern. A beneficiary until the Soviet Union’s dissolution of cheap petroleum from Russia, Ukraine’s industry is now withering for want of fuel. And Ukraine simply cannot afford to shop for crude on the world market.

The Russians had offered to sell 15 million metric tons of oil at special rates, but the Ukrainians say they need three times that amount. Without giving specifics, Yeltsin said Russia will increase somewhat the quantity of oil guaranteed to Ukraine, but that upheaval in Russia’s energy sector means output this year will plummet by 40 million tons.

“We cannot fully meet Ukraine’s demands,” Yeltsin said.

But, in what appeared to be the start of the “oil union” advocated by Ukraine’s prime minister, Leonid Kuchma, Yeltsin said energy specialists from Ukraine will fly to western Siberia on Monday to see how they can get thousands of now idle wells back into production.

Every drop of crude obtained will be supplied to Ukraine, Yeltsin said. Other former Soviet republics without petroleum can also get in on the act, he added.

Eliminating another divisive issue, the two presidents agreed to appoint Vice Adm. Eduard Baltin, 56, a former submariner and Hero of the Soviet Union, as commander of the joint Russian-Ukrainian Black Sea Fleet.

The Russians also said they wholeheartedly support Ukraine’s newfound desire to repay its share--fixed at 16%--of the Soviet foreign debt, in exchange for receiving an equivalent share of Soviet assets. Before, the Ukrainians had let the Russians assume both credits and debits.