A Soviet concession has been made in the nuclear arms control negotiations to permit the testing of long range cruise missiles launched from the ground or the sea, American sources said yesterday.
This projected compromise was described yesterday as resolving one of several major issues still in dispute in the stratiegic arms limitation talks, (SALT).
Contrary to published reports, administration sources said, no agreement yet has been reached on extending the range limitations of 2,500 kilometers, or about 1,550 miles, for air-launched cruise missiles.
The United States is seeking enough-latitude in these range definitions to permit the low-flying, jet-powered weapons to take their required evasive action in reaching a target 1,550 miles away. The difference between actual distance and flying distance could vary by 25 or 30 per cent or more.
Depending on how operational range is defined, it can come out to either 2,500 kilometers or, for example, the 3,000-kilometer range the Defense Department seeks. This variation took on added significance when President Carter canceled the B-1 bomber, choosing instead to rely on aging B-52 Bombers armed with cruise missles as an important part of the nuclear arsenal.
Also unresolved, and not near agreement, informed sources said yesterday, is difference on foreclosing the transfer of nuclear technology. The United States is anxious to obtain language which will have open the sharing of cruise missile technology with Western European allies. The Soviet Union seeks to prevent that.
Administration sources regard the compromise reached to permit testing of long-range versions of ground-launched and sea-launched cruise missiles as an important American gain. It also is expected to help ease concerns among Western European allies that these weapons would be barred from allied defense.
The Soviet Union sought to limit testing of the ground and sea versions of cruise missiles to 600 kilometers, or 373 miles. Under the reported compromise, they now could be tested at long range, generally similar to the range for air-launced cruise missiles.
Before this Soviet concession, however, administration officials had maintained that, if necessary, they could adequately develop long-range ground and sea cruise missiles by air-launched tests. One cruise missile, the Navy's Tomahawk, is designed for use in all three environments. The Air Force's design, by Boeing, is air-launched.
All these range limitations would be in a three-year protocol of a treaty extending to 1958. As a result, there is disagreement over how significant they will prove to be in any event, as long as range cruise missiles are still in the development stage.
There is speculation inside the administration that the Soviet Union agreed to the compromise to speed up conclusion of the SALT agreement, and perhaps also because it may plan to develop its own long-range, ground-launched and sea-launched cruise missiles.
Disclosure of the new Soviet concession amounted to what insiders call "the first counterleak" supporting the administration's side of the SALT controversy.
The SALT "battle of leaks" is often vigorous, in the political battle over arms control. But the "leaking" has reached exceptional proportions during current negotiations.
Sen. John Culver (D-Iowa) yesterday called on President Carter "to halt the selected disclosures by administration sources of sensitive details of the SALT negotiations, and to lay before the American people as much about the emerging agreement as can properly be released at this time."
Culver two weeks ago called for an investigation of "apparent leaks" from hearings before the Senate Armed Services committee, of which he is a member. Those leaks were critical of the administration. Culver said that yesterday he telephoned the White House to protest leaks in a New York Times report on Soviet concessions over cruise missiles.
That account, reporting multiple Soviet concessions, some of them denied yesterday by administration sources, "appears to be part of an administration selling job" this time around, Culver said.
"In order to clear the atmosphere," Culver said, "the administration should set ground rules regarding disclosures that are fair and understandable to all parties concerned."