The Energy Department is privately urging energy companies to take extra precautions against terrorism, in part out of concern that Libya or Iran might strike at key U.S. energy facilities.

In addition, the National Security Council has created a special interagency task force to assess the vulnerability of domestic energy systems and to study possible U.S. responses to a wide variety of energy emergencies at home and abroad."Energy-related terrorism in the United States would be a particularly significant threat" in a military crisis involving the Soviet Union, said an internal Energy Department report obtained by The Associated Press.

"However, even in the absence of a superpower confrontation, there is the possibility that potential Third World adversaries could sponsor attacks on the energy infrastructure in the United States," the report said.

The report was prepared in December 1987 to describe the early stages of the department's accelerated effort to improve national energy security. It was deemed too sensitive to make public, although a sanitized version was presented to Congress last year, and a similarly limited edition was published last month.

Electric power companies, considered the most vulnerable segment of the energy industry, have begun acting on the Energy Department's anti-terrorism warnings, according to sources familiar with ongoing discussions between industry and government.

But other energy businesses, including the oil industry, have been reluctant to join the program, according to the sources, who spoke on condition of anonymity.

The report said a natural disaster such as an earthquake or disruptions of world oil supplies are more likely to cause a national energy emergency but that a terrorist incident would be more serious.

Among the initiatives taken to improve coordination with private energy companies was a program of special security training for company officials at the Energy Department's Central Training Academy at Albuquerque, the report said.

A key reason for the initiative, according to department officials and documents, is growing concern about "techno-terrorism," the use of hard-to-detect plastic explosives, hand-held missiles, electronic surveillance gear or other sophisticated devices to carry out politically motivated acts of sabotage.

The heightened alert also reflects a fear of retaliatory strikes by Libya and Iran, countries accused by the United States of supporting terrorism, the sources said. American bombers attacked Libya in April 1986, and Iranian oil facilities in the Persian Gulf were hit by U.S. forces in October 1987 and April 1988.

Taking its cue from the Energy Department, the Nuclear Regulatory Commission last December imposed new measures to strengthen protection against possible terrorist attacks at the few facilities it oversees that handle weapon-grade nuclear materials. However, the measures were not applied to nuclear power plants, which also are under NRC jurisdiction.

The Energy Department report said the most vulnerable segment of the energy system is the electric power grid, which is stretched across long distances in many remote, unprotected areas. Repairing or replacing critical power plant components such as generating stations can take weeks or months, it said.

Less vulnerable, but still a source of concern, are oil refineries and offshore production facilities, oil and natural gas pipelines and coal transport links.

In 1987, an Army Special Forces team acting as terrorists staged a moch attack that "knocked out" power substations, an emergency operations center and valves of the Strategic Petroleum Reserve in Louisiana and Texas. The Energy Department says it is tightening security for the oil stored against an embargo.

The report noted that serious power disruptions have been carried out by terrorist organizations in Western Europe and parts of Africa and South America.