The Central Intelligence Agency, in a new annual report that listed thousands more international terrorist incidents that it had counted previously, warned yesterday that such attacks are growing bloodier than ever.

"The number of terrorist incidents apparently aimed at causing casualties -- most notably assassination attempts -- increased dramatically in 1980," the agency said, attributing much of the rise to well-planned campaigns by Libya and other governments and organizations in the Middle East.

Even more dramatic was the overall rise in CIA statistics on terrorism since 1968, when it began keeping computerized records on the worldwide phenomenon. The agency said that its previous data had been too dependent on "U.S. sources" and that it now is satisfied that its records are "complete and current."

The report also listed several new categories, including "threats" and "hoaxes," which had never been counted.

The CIA study did not make special mention of the new categories but did announce, in a footnote, that "statistics in this publication replace all statistics in our previous surveys."

The agency's National Foreign Assessment Center, which produced the report, said there were 6,714 international terrorist incidents from 1968 through 1980, including 760 last year.

By contrast, last year's report said there had been only 3,336 such incidents from 1968 through 1979, with a peak of 413 in 1976.

The 6,714 total includes 1,008 threats, 58 hoaxes and 121 cases of "conspiracy," another new category. The revision coincides with a new emphasis, within the administration and on Capitol Hill, on dangers of world-wide terrorism.

According to the CIA, American citizens, especially businessmen, remain a primary target of terrorist attacks, particularly in the Middle East and Latin America. Six Americans in El Salvador, two in Turkey, one in the Philippines and one on the West Bank were killed in international terrorist attacks last year, and 94 Americans were wounded, the report said.

The next "most victimized nationalities" were, in order, Israelis, Soviets, Turks, Iraqis and Libyans, the CIA said.This was a notable changee from 1979 when the favorite targets were Americans, British and French.

"Last year marked the first year that a large number of deadly terrorist attacks were carried out by national governments," the study said. "The Libyan government's assassination campaign against dissidents living in Europe and the exchange of terrorist attacks on diplomats in the Middle East were the most noteworthy examples. . . ."

The CIA also noted "a sharp increase in right-wing terrorist activity in Europe," with bloody attacks at the Munich Oktoberfest and at the railroad station in Bologna, Italy, ranking among the worst terrorist incidents ever recorded.

Casualties from those two events were included in the CIA's overall count of 642 killed and 1,078 wounded in international terrorist attacks last year. But in general, the report cautioned, "most terrorist activity by right-wing groups will remain domestic in nature and thus will not be reflected in our statistics."

The CIA said "the Soviets are deeply engaged in support of revolutionary violence" and "such violence frequently entails acts of international terrorism."

As for Libya, where the Soviets sell large quantities of arms, the CIA called the regime of Muammar Qaddafi "the most prominent state sponsor of and participant in international terrorism."

In addition to a clear and consistent pattern of Libyan aid to almost every major international terrorist group, the report said, "our records list 14 attacks by Libyan assassination teams in Europe and the United States" last year against dissident Libyan students and expatriates.

Eleven Libyan exiles were murdered and one wounded, in seven countries.