BONN, JUNE 4 -- Chancellor Helmut Kohl today won parliament's backing for his government's acceptance of the broad outline of a proposed U.S.-Soviet accord to slash arsenals of European-based nuclear missiles.

In an apparent slight hardening of Bonn's stance, Kohl said the deal must leave untouched the U.S.-controlled warheads on 72 West German Pershing IA missiles.

Kohl's governing coalition, in an announcement Monday, had affirmed a desire to keep the missiles but had not referred specifically to the warheads. The Soviet Union has said that the warheads must be removed in any deal.

Kohl told parliament today, "The 72 Pershing IA missiles with their American warheads cannot be included in a U.S.-Soviet 'zero solution.' "

The accord would remove from Europe all medium-range missiles -- those with ranges of between 600 and 3,500 miles -- and shorter-range missiles in the 300-to-600-mile category.

{In Venice, the White House released a statement by President Reagan saying the West German decision lays the foundation for an arms agreement. A spokesman said it also moves the superpowers a little closer to a new summit meeting.}

Bonn's decision removed an important obstacle to conclusion of the U.S.-Soviet treaty. The Pershing IAs' warheads nevertheless remain at the center of one of the few remaining disputes in the Geneva negotiations over the accord.

The Pershing IAs can travel about 450 miles and therefore fall in the category of shorter-range weapons to be banned. But Washington publicly agrees with Bonn that they are "third-country systems," like the arsenals of Britain and France, and therefore outside the scope of the U.S.-Soviet talks.

The Soviet Union has said that West Germany can keep the 25-year-old missiles, but that the U.S.-controlled warheads must go. Otherwise, Soviet officials have argued, Moscow would have to give up its approximately 130 short-range missiles without making a dent in NATO's arsenal of similar weapons.