U.S. Sends Arms Pact Protest to Soviets : Missiles: American inspectors were not allowed to X-ray three containers at a Soviet factory.

In a second serious dispute over missile verification, the Bush Administration has officially protested the Soviet Union’s refusal to allow X-rays of three missile containers at a plant monitored under the 1987 Intermediate-range Nuclear Forces Treaty, U.S. sources confirmed Wednesday.

Secretary of State James A. Baker III personally protested Soviet behavior in a letter to Foreign Minister Eduard A. Shevardnadze this week, a State Department official said.

Sources said the refusal occurred last weekend at the Votkinsk missile plant.

Last week, it was disclosed that East Germany has been secretly in possession of 24 Soviet-made SS-23 missiles. The INF treaty bans Soviet and American missiles with a range of 300 to 3,400 miles, and the SS-23s have a range of 550 miles. U.S. sources said it would be a violation of the treaty if the missiles had been transferred to East German control after the agreement was reached. A State Department official said Wednesday that the Administration was dissatisfied with the Soviets’ explanation of that incident.

Baker’s personal intervention in the Votkinsk case indicates the Administration is concerned that unless the matters are quickly resolved, conservative critics will use the two episodes to attack new strategic arms treaties. Both a nuclear arms pact and a conventional arms reduction agreement are expected to be signed this year.

The protest, although rooted in a narrow technical dispute, is believed to be the highest-level complaint ever concerning the INF treaty.

The episode involves a controversial X-ray device called a “cargoscan.” It is now installed at the Votkinsk assembly plant, where on-site U.S. inspectors monitor missile-containing canisters.

The purpose is to ensure that none of the intermediate-range SS-20 missiles are produced and sent out under the guise of SS-25 long-range missiles, which are not covered by the INF treaty.

The SS-25 is essentially a variation of the SS-20. The X-ray machine can differentiate between the two.

The INF treaty provided that such a machine could be used at Votkinsk after a memorandum covering its use was signed. Considerable delay was encountered in building and testing the machine. In the interim, the missile canisters were examined from the outside, and any eight of the canisters could be randomly opened and inspected by the Americans during one year.

Although the memorandum was signed over a year ago, the machine was put in place only last month. The United States declared it operational, but the Soviets protested that some technical factors did not conform precisely to the description in the memorandum.

In essence, the Soviets want to ensure that the machine does not photograph more of the missile than necessary to establish its dimensions.

The Soviets refused to allow the machine’s use before ironing out the differences. They also delayed the departure of one missile canister for at least a day in apparent hopes of working out the dispute.

But on Saturday, they moved three canisters out of the plant. U.S. inspectors were allowed to examine them in the old manner, but the locomotives pulling the canisters in railroad cars were not stopped to permit the X-ray machine to be used.

In replying to a U.S. note regarding East Germany’s possession of SS-23 missiles, Moscow claimed the weapons were transferred to East Germany before the U.S.-Soviet treaty took effect, U.S. officials said. Thus, the East Germans were not required to disclose the weapons because East Germany was not a party to the INF agreement, and the Soviets were not required to destroy the missiles because they no longer owned them.