Iran and Iraq may join North Korea in presenting a ballistic missile threat to the mainland United States within the next 10 years, according to a declassified version of a new national intelligence estimate released yesterday.

In the next few years, Iran "could" test an ICBM capable of delivering a small, nonnuclear payload to the United States using technology and assistance it has received from Russia, according to the report by the CIA and other members of the U.S. intelligence community. "In the last half of the next decade," the report adds, Tehran could test a ballistic missile capable of carrying a nuclear-weapon-sized payload to most of the United States.

Iraq, according to the report, could test a North Korean-type ICBM that could hit the United States in the next 10 years, "depending on the level of foreign assistance." Analysts differ, however, on whether it would take 10 or 15 years before the Iraqis could test an ICBM that could carry a nuclear warhead.

The report is an outgrowth of a controversy that developed two years ago, when Congress criticized a national intelligence estimate that appeared to underestimate the ballistic missile threats facing the United States.

In July 1998, a commission headed by former defense secretary Donald Rumsfeld criticized the earlier analyses and forced a revision in analytical approach. The intelligence community was further embarrassed several months later after North Korea launched an unexpected three-stage missile, called the Taepo Dong-1, which unsuccessfully attempted to put a payload in space.

North Korea was described in the report released yesterday as being able to convert the Taepo Dong-1 to an intercontinental missile, but the experts said it was more likely a larger model, the Taepo Dong-2, would be used to carry a warhead to the United States. The analysts wrote that the North Koreans could test the larger missile "at any time," but it could be delayed "for political reasons." U.S., Japanese and South Korean officials are attempting to get Pyongyang to delay its testing in return for financial and agricultural aid.

The ballistic missile report, which is mandated by Congress, could increase support for calls for President Clinton to approve next year building a limited missile defense to protect the United States against an attack. Deputy Secretary of State Strobe Talbott went to Moscow this week for talks with the Russian government about a U.S. plan for building a 100-missile defense site in Alaska--a deployment that would require changes in the 1972 ABM Treaty.

The intelligence analysts concluded that North Korea, Iran and Iraq are building their ICBM forces mainly for "coercive diplomacy" and to deter preemptive U.S. use of its far larger nuclear missile forces against them.

A senior intelligence official who participated in the study said yesterday that the spread of medium-range missiles "has created an immediate, serious and growing threat to U.S. forces."

The report noted that Russian forces will "decrease dramatically--well below arms control limits--primarily because of budget restraints."

By 2015, according to the report, China "will likely have tens of missiles targeted against the United States" with small nuclear warheads "in part influenced by U.S. technology gained through espionage."