Yeltsin Ends S. Korean Visit With Treaties : Diplomacy: Russian president forges military and economic agreements with a former enemy and pledges new actions against the north, an old ally.

Russian President Boris N. Yeltsin wound up his first visit to Asia on Friday by forging new military and economic agreements with South Korea, a former enemy, and pledging new actions against Communist North Korea, an old ally.

After the defense ministers of South Korea and Russia signed an agreement for military exchanges, Yeltsin signed a declaration with President Roh Tae Woo that set the stage for widespread South Korean participation in Russian economic development.

In an irony of history, Yeltsin and Roh declared that they share the view that Russia’s “political stability and economic prosperity are essential to maintaining peace” in Asia and the world--with Roh offering Yeltsin a pledge to assist Russia, the south’s former foe. Their statement contained no corresponding reference questioning the stability or prosperity of South Korea.

South Korea was a fragile, poverty-stricken nation in 1950-53 when the Soviet Union supported Communist North Korea’s aggression against it. Only American-led intervention preserved South Korea’s existence in that war.

The United States, with 37,000 troops still stationed here as a deterrent against North Korean aggression, stands to benefit from the shifts in Moscow’s alliances, which Yeltsin underscored Friday.

The defense agreement spelled out official exchanges planned for next year, including mutual visits by the defense ministers or chairmen of the joint chiefs of staff of the armed forces; there also will be visits by vessels of the respective navies to Pusan and Vladivostok.

That would mark the first extensive contacts between active-duty officers and leaders of the two military establishments. It would serve as a counterbalance to long--and still continuing--Russian-North Korean military interchange.

Earlier, Yeltsin had offered to sell South Korea military equipment and technology.

In a news conference with Roh, Yeltsin declared that, while cessation of Russian aid would inevitably force North Korea to halt its nuclear program, Moscow also will pressure Pyongyang politically to stop its suspected weapons development.

Yeltsin promised to deliver to South Korea by year’s end information on former state secrets about the Korean War.

They are expected to provide more details about North Korea’s aggressive intent in attempting to unify the Korean Peninsula through force.

The Pyongyang government of President Kim Il Sung, who was installed as the North Korean leader after World War II by the Soviet Union, still contends that South Korea and the United States started the Korean War.

U.S. officials, such as Ambassador Donald Gregg, have described political help from Moscow as valued and appreciated in easing tensions on the Korean Peninsula. Fearing that North Korea might develop nuclear weapons, the Bush Administration earlier this year postponed implementation of a second phase of U.S. troop withdrawals.

Yeltsin and Roh also agreed on unspecified discussions among nations of Northeast Asia to build “mutual confidence and understanding” on security issues.

On the economic side, they welcomed an agreement signed here by business people from both countries to begin studying the development of natural gas fields in Yakutsk and the building of a pipeline through China, North Korea and South Korea.

That unprecedented multibillion-dollar project could take more than two decades to complete.

Roh and Yeltsin also listed more immediate undertakings between their nations, including: production of telecommunications equipment; installation of optical fiber lines for telecommunications in Russia, and development of offshore gas fields near Sakhalin Island.

They spoke of joint ventures in machinery, electronics, metallurgy, textiles, shipbuilding, aerospace and other scientific and technological areas.

Yeltsin acknowledged that Russia must carry out more reforms--and pledged to do so--to win investment from increasingly skeptical South Korean business people, some of whom have been burned by broken promises and bureaucratic chaos in Russia.