President Carter's outspoken support of human rights around the world has had "a great, positive echo in the countries of Eastern Europe."

The speaker is Milovan Djilas, a post-war leader of the Yugoslav Communist Party who for more then 20 years has also been its best known and most outspoken critic.

"Everybody in Eastern Europe knows about what the new American administration has been saying," Djilas continued in an interview in his apartments in this Yugoslav capital.

"It is something like the beginning of America acting once again like her traditions. Carter cannot change the situation in Eastern Europe, but maybe be can influence governments to be more careful, more respectful of laws," he said.

Yet, Djilas said, Carter must proceed with the utmost caution. He warns that attacking the Soviet system head-on is futile and that the Soviets also cannot be "blackmailed" into concessions on human rights through trade restrictions such as those championed by Sen. Henry M. Jackson (D-Wash.).

"The Carter approach thus far is right and should be continued. But that doesn't mean he should quarrel with Brezhnev," the Soviet Communist party chief.

What is a good in Carter's policy is that he is not only insisting on human rights in Communist ruled countries, but everywhere - in Brazil and in Rhodesia.

"What I am afarid of, if anything, is that American pragmatism, in the form of the multinational corporations, will not follow Carter's ideals. Profits are important, but in our time there is more to survival."

Djilas, once a president of the Yugoslav Parliament and confidant of President Tito until 1954, will be 66 in June. His hair is gray, his during the conversation in his face is pale and he fidgeted slightly during the conversation in his book-lined study.

Djilas has been a political dissident for 23 years. He has spent nine years in jail as a political prisoner largely because of his books, first, in 1957, "The New Class," which was a harsh indictment of his country's post-war leaders for their failure to fully reform communism and for the privileges they set up for themselves. He also wrote, and was jailed for, "Conversations With Stlain."

Last week, however, Djilas said he received the first threat to his life and his wife's in the form of an anonymous letter. Djilas believes it was probably from the police and does not think it is "a serious threat, but is symptomatic of the atmosphere here."

The letter arrived after Djilas told reporters that i his opinion Yugoslavia has jailed at least 600 political prisoners, putting this country, in proportion to its 22 million population, in the same category as the Soviet Union.

Although the Belgrade government is used to criticism from Djilas, the prisoner allegations stung for several reasons. The Communist government here dislikes being compared in any way - but especially in terms of human rights - to the Soviets.

Since Tito's break with Stalin in 1948, Yugoslavia has stayed out of the Soviet-dominated Warsaw Pact and cultivated it s image as the unofficial leader of the nonaligned nations.

Secondly, Belgrade prides itself as being the most open of any East European society.

Further, Djilas' comments landed as the Yugoslavs are preparing to host the 1975 Helsinki Agreement on European Security and Cooperation.

The Yugoslav Foreign Ministry attacked Djilas as being part of a propaganda campaign directed by foreign interests and intent on poisoning the atmosphere and forcing Yugoslavia, in the minds of outsiders, into both the East-Winds confrontation over human rights, and into the Soviet category in that field.

Most Western criticism over human rights thus far has been directed at the Soviet Union and Czechoslovakia many and Poland.

In fact, Yugoslavia is clearly the most open Communist society in the East. The stores here are loaded with Western goods. Western movies, newspaper and magazines are readily available, although some issues are occasionally banned. Hundreds of thousands of Yugoslavs work in Western countries, bringing back money and ideas. Some 6 million Yugoslavs have passports and they took 14 million trips abroad last year.

Djilas acknowledges all that but calls it "the tourist view" of his count [TEXT OMITTED FROM SOURCES]

"In many ways, Yugoslavia is very different from the Soviet Union. But when it comes to persecution of political opposition, especially in the last several years, I don't see any difference," he says.

"You can be persecuted for private talking, gossiping in a room about the regime, and may be arrested. The majority of people are arrested this way and get five-12 year sentences.

"There is no real underground opposition here, no literature, just small groups. But an opposition does exist here which in terms of the intelligentsia may actually be larger than in Russia," he claims.

That there is some truth to what Djilas says is reflected by government officials who privately confirm the likelihood of amnesty for an unspecified number of prisoners sometime before the June 15 conference and perhaps before Tito's 85th birthday May 25.

Included in those expected to be released is author Mihajlo Mihajlov, 42, who was arrested in February 1975. As a relatively young critic and political dissenter, Mihajlov personified what is probably the most embarrassing and well-known case confronting the Belgrade authorities.

"Yugoslavia is smart enough to respond" to the growing pressure for more human rights, he says," to differentiate itself from Eastern Europe as she really is different in economic, cultural and travel terms. So now, she may also become different in terms of persecution."

Yugoslav officials do not deny that there are political prisoners here and they define them this way, in the words of one top government official who asked not to be identified:

"Yugoslav political prisoners are not opponents to the regime. They could be more or less described as stooges of some foreign interests. So they cannot be treated as some national opposition. They have no political influence in this country but they must be prevented from such aspirations or activity because Yugoslav foreign policy has no alternative. It must be as it is - permanently nonaligned.

"So-called liberals or dogmaticists like to include Yugoslavia in bloc confrontations. Going along this line would be a great threat to our future.

"Regardless of the propaganda, we don't send them to prison just because of their views or thinking. It's their own right to try and materialize their opinion through propaganda and political activities."

Despite their efforts to keep their distance from the Soviets, Belgrade officials belive it was "a great provacation" for Carter to write to Soviet dissident Andrel Sakharov and meet at the White House with Soviet exile Vladimir Bukovsky.

Djilas disagrees, because "at the end, detente of human rights."

All of the human rights movements that have surfaced in Eastern Europe in recent months spring from the Helsinki accords and their provisions on human rights, which were read by people in East, and Djilas. "Helsinki also destroyed some of the Eastern propaganda that the West is antagonistic. But without this campaign in the West," Djilas said, the human rights gains still would not come.

"Even now" the combination of the dissendent movement and the Western campaign, as he calls it, show results, he said. "Mihajlov and others will probably be released, he said. In Prague, more signers of Charter 77 would have been arrested and the same, he believes, is true of other Soviet dissidents such as Sakharov, and of Polish workers groups.

"Even me," he said, "I probably would have been arrested due to my interviews."