May 8, 1982

Unemployment in April rose to 9.4 percent of the labor force, the highest level in 40 years, largely because of layoffs in manufacturing industries and a decline in retail jobs, the Labor Department reported today. In reporting an increase of four-tenths of a percentage point in the unemployment rate last month, the Bureau of Labor Statistics said that 10,307,000 people were jobless in April, an increase of 450,000 over March. The bureau found more than 99,340,000 people still employed, but this was 152,000 fewer than a month ago. In New York, the state unemployment rate dropped from 8.2 percent in March to 8.1 percent in April, while the New York City rate dropped sharply to 9.1 percent from a 12-month high of 10.1 percent in March. (Page 9.)

The news of the jump in the unemployment rate comes at a time when the Reagan Administration, the financial markets and a large majority of economists have begun to forecast an upturn in the business cycle. They say the upturn should come either in the current April-June quarter or, at the latest, in the next quarter, following the scheduled 10 percent cut in personal income taxes next July 1. The rise in the unemployment rate to 9.4 percent could make those forecasters somewhat more cautious. James Capra, an industrial economist at the New York Federal Reserve Bank, said: ''It is not a good situation. Not many forecasters had the unemployment rate topping out as high as 10 percent, but with this jump it could happen.''

In an effort to protect its task force in the South Atlantic and to increase military pressure on Argentina, Britain announced tonight that it would treat as hostile any Argentine warship or plane found more than 12 miles from the mainland coast. In effect, the declaration constituted a warning to Argentina to keep its planes at their bases and its ships in port or face attack. It extends the territory covered by the air and sea blockade imposed in a 200-mile zone around the Falkland Islands on April 30, vastly increasing the area to be patrolled by the British fleet's ships and planes. The Argentine coastline extends for about 2,500 miles. Argentina Dismisses Move Defense Minister Amadeo Frugoli said Argentina would respond to what he called growing aggression by Britain, and Argentine naval officers said the British fleet in the South Atlantic did not have the power to enforce the extension of the blockade around the Falklands. (Page 4.)

A senior State Department official said today that the United States felt that unless Argentina agreed soon to withdraw its forces from the Falkland Islands, Britain would invade the islands ''and prevail in the end.'' In a briefing for a few reporters, the official said the United States, despite backing Britain in the dispute, was still hopeful of avoiding what he called ''more terrible fighting.'' But he said Washington was frustrated by Argentina's refusal to accept any formula for a settlement that called for a withdrawal of Argentine troops without a guarantee in advance of Argentine sovereignty over the islands. At the United Nations, Secretary General Javier Perez de Cuellar said he had perhaps two days to achieve a cease-fire that would be acceptable to both Argentina and Britain. (Page 5.)

The Supreme Court today turned down, without comment, the appeal by RKO General Inc. of the Federal Communications Commission's decision to strip the company of its right to operate a highly profitable Boston television station. The F.C.C.'s action was upheld last year by the United States Court of Appeals here. Permission to operate WNAC-TV, which broadcasts on Channel 7 in Boston, is now expected to go to the New England Television Corporation. Under a former corporate identity, that company has been challenging RKO's Boston license since 1968.