The main federation of private businessmen called on President Anastasio Somoza today to "resign immediately" and turn over power to the rebel-backed provisional junta.

The Superior Council of Private Enterprises said the five-member junta should serve until a new government can be formed "to include all opposition forces in Nicaragua and the productive sectors of the country."

One participant in the meeting made clear the council's view that "no new government can include any members of the National Guard or any one who has been part of the Somoza regime."

The group had called for Somoza's resignation June 6, but today's decision by the business leaders to accept even the temporary authority of the junta was a considerable victory for the rebel Sandinista National Liberaton Front.

Approved by a 16-member committee of industrialists in Managua this afternoon, the statement called on "members of the army and especially the air force pilots to stop the inhuman massacre and pointless destruction of the homes and property of Nicaraguans."

In the last year, the council has attracted wide support from the private sector and is the recognized umbrella organization for industrialists, bankers and professional groups.

The committee met against a back-drop of intense speculation over the meaning of Somoza's decision to call a session of the national congress for Thursday.

There was no indication from Somoza that he would do other than try to rally support when the congress meets.