Letup on CIA curbs is backed

The CIA will likely have more power to do surveillance on US citizens now that the Senate Intelligence Committee has agreed with President Reagan's plan to loosen domestic spying curbs on the agency. But the panel disagreed with the provision allowing the agency to infiltrate and influence domestic groups.

It also wrapped up its inquiry on CIA director William J. Casey and reaffirmed that there was no basis for finding him ''unfit'' to head the agency.

Reagan has authority by his signature alone to issue new marching orders for the CIA. But because of concern over possible abuses of civil liberties, the administration has been talking with the House and Senate intelligence committees.

The Casey investigation began in July after Max Hugel, then chief of CIA covert operations, was forced to resign because of questionable past business dealings.