The Senate gave swift and unanimous approval last night to nominations of 24 officials to State Department posts, ending a monthlong "hold" imposed by Sen. Jesse Helms (R-N.C.) and other conservative senators. Four other nominees remain in limbo pending votes next week.

The bloc vote, taken in a fast-emptying chamber as senators headed home after a grueling week, will allow several key nominees to take office. They include Thomas Pickering as ambassador to Israel and Elliott W. Abrams as assistant secretary for inter-American affairs.

The four who remain on hold are Richard R. Burt as ambassador to West Germany, Rozanne Ridgway to replace him as assistant secretary of state for European affairs, Edwin Corr to replace Pickering as ambassador to El Salvador and John A. Ferch as ambassador to Honduras.

The action reflected an agreement between Helms and the State Department on the fate of six conservative officeholders whom conservatives had wanted "taken care of" before they consented to release the new nominations for debate.

Both sides declined to reveal details of the agreement, saying the State Department would make the announcements soon. "I'm very satisfied," Helms said. "This has been a good week."

Senate Majority Leader Robert J. Dole (R-Kan.) said the agreement was worked out among Helms, Foreign Relations Committee Chairman Richard G. Lugar (R-Ind.) and new Undersecretary of State John C. Whitehead. Whitehead's nomination was cleared earlier this week.

Other nominations approved were:

Ambassadors: Peter S. Bridges, Somalia; Fernando E. Rondon, Ecuador; Charles A. Gillespie, Colombia; Sheldon J. Krys, Trinidad and Tobago; Lowell C. Kilday, Dominican Republic; Harry G. Barnes, Chile; Robert L. Pugh, Mauritania; Edward J. Perkins, Liberia; Lewis A. Tambs, Costa Rica; Edward M. Rowell, Bolivia; Paul J. Hare, Zambia; John D. Scanlan, Yugoslavia; David G. Newton, Iraq; Lannon Walker, Senegal; Thomas A. Nassif, Morocco; Richard T. McCormack, Organization of American States; J. William Middendorf II, European Community; L. Craig Johnstone, Algeria, and Nicholas Ruwe, Iceland.

Assistant secretaries of state: John D. Negroponte and Douglas W. McMinn.

Charles E. Courtney was approved as associate director of the U.S. Information Agency.