BONN, JUNE 15 -- The Soviet Union maneuvered with both NATO and the Warsaw Pact today in a continuing effort to meet the challenge to its strategic position posed by imminent German unification.

The North Atlantic Treaty Organization in Brussels announced rejection of a Soviet proposal for early East-West negotiations aimed at removing from Europe all short-range nuclear forces -- those with ranges of less than 300 miles. A NATO spokesman recalled the allied position -- issued in response to earlier Soviet suggestions for such talks -- that they can begin only after an agreement on reduction of conventional weapons under negotiation in Vienna.

A statement specified, however, that the Soviet proposal will be discussed by the 16 NATO leaders at a special summit conference July 5-6 in London called to adapt alliance strategy to the new military situation created by far-reaching changes in Central and Eastern Europe.

But the Soviet suggestions, which the spokesman said were recently presented to the United States, contained provisions likely to be rejected by Washington and its NATO allies even after an accord in Vienna. Among them, according to reports from Brussels, were including France's short-range nuclear weapons in the next round of nuclear arms reductions and considering air-launched warheads as well as those fired from ground stations or artillery within the short-range weapons talks.

In that light, the reiterated Soviet proposals seemed aimed mainly at German public opinion. Removal of all nuclear weapons from European soil has been a popular theme here and is likely to become attractive as an issue in the campaign for elections scheduled in December.

With removal of medium-range weapons already agreed, the short-range weapons remaining are largely on German soil. If fired, they would be used largely against targets in West and East Germany, a deployment Germans find increasingly difficult to accept.

The Soviet Union has been probing relentlessly in a variety of forums for ways to reduce the strategic impact of a united Germany that would retain full NATO membership. Strong public demand for removal of short-range nuclear weapons from Germany would be a step in this direction.

In the East Berlin suburb of Strausberg, meanwhile, the Warsaw Pact defense ministers concluded a two-day gathering without reaching clear-cut decisions on the future of their Soviet-led alliance. In what appeared to signal differences of opinion on how fast the pact should evolve, Soviet Defense Minister Dmitri Yazov said the Warsaw Pact nations must retain their military ties until NATO shifts away from a Cold War orientation.

"Self-removal and self-withdrawal from the European scene by the Warsaw Pact organization would complicate the current European process rather than facilitate it," he told the Soviet news agency Tass.