Secretary of State George P. Shultz has endorsed rebuilding or relocating about half of the United States' embassies and consulates as part of a plan to combat terrorism, a department official said yesterday.

An advisory panel on overseas security Shultz appointed last July recommended that the State Department beef up security at 126 of its 262 embassies and consulates, create a diplomatic security bureau with more than 1,000 officers, and establish a board of inquiry to establish accountability for terrorist or other violence.

It also suggested that the department consider closing some of its consulates.

Headed by retired vice admiral Bobby Ray Inman, former deputy director of the Central Intelligence Agency, the panel made 91 recommendations.

A State Department spokesman said it was "purely coincidental" that the report was released while U.S. citizens were being held in Beirut.

Shultz has "approved of the recommendations in principle" and asked that they be "implemented quickly," said Robert Lamb, assistant secretary of state for administration, who is overseeing the recommendations' fulfillment.

Lamb, briefing reporters, said that his agenda constituted "an effort to take the offensive against the range of threats against our embassies today."

The panel said that implementing its report would require legislation appropriating $3.5 billion to rebuild and refurbish embassies over five years, $30 million for the diplomatic security bureau and substantial additional funds for the other proposals.

The advisory panel said that many of the embassies fail to meet the department's minimum security standards because of poor location or inadequate safety structures, among other reasons.

"We knew that we had a problem," Lamb said, "but we did not expect it to be of that magnitude."

Lamb said 75 embassies would have to be rebuilt. The United States can no longer add cement walls or special windows to rectify security problems, he said. He added that the most vulnerable embassies are not in any one region but are "scattered all over the world."

But the abbreviated version of the report, which was released yesterday, said that Western Europe, Latin America and the Middle East were expected to continue to be "the most terror-prone regions."

The panel also recommended that the State Department:

*Upgrade the training and performance standards for embassy guards.

*Revise security standards for ancillary facilities and residences, including more effective use of armored vehicles.

*Coordinate the protection of foreign diplomats and visiting dignitaries in Washington.

*Improve and expand contingency planning for U.S. embassy crises.

*Address the safety requirements of U.S. civilians working in U.S. embassies and consulates.

The panel also made classified recommendations geared toward redressing espionage activities and what the report described as "the steadily worsening climate of terrorism."

It did not recommend decreasing the number of Soviet and other foreign staff workers in the U.S. embassies in Moscow and other Soviet-bloc countries.

But the State Department began replacing some Soviet employes with Americans in the embassy in Moscow several weeks ago, Lamb said.