Arab opponents of U.S. policy in the Middle East have responded to new American-Israeli strategic cooperation accords by deciding to forge similar ties with the Soviet Union.

A summit of the five nations belonging to the so-called Steadfastness and Confrontation Front held in Libya this past weekend agreed to join forces with Moscow "to develop a strategy in Arab-Soviet relations" capable of offsetting the new American-Israeli alliance, according to the final communique.

The five leaders--Muammar Qaddafi of Libya, Presidents Hafez Assad of Syria, Benchedid Chadli of Algeria and Ali Nasser Mohammed of South Yemen plus Palestine Liberation Organization leader Yasser Arafat--also called for "decisive measures" against the American-backed government of Egyptian President Anwar Sadat. In addition, they pledged to use "all Arab economic resources, including oil and Arab assets in U.S. banks," to combat the new alliance.

The summit was the latest of many indications of the growing polarization of the region between allies of the United States and those of the Soviet Union under the impact of the heightened American-Soviet rivalry since the advent of the Reagan administration.

The administration's tendency to view the problems and issues of the Middle East primarily in East-West terms has begun to have repercussions whose ultimate consequences are still difficult to predict but that could well trigger precisely what Washington hopes to avert--a far greater Soviet involvement in the region.

Already, Moscow's allies, increasingly worried, are responding not only by seeking to close ranks, as seen at their latest summit, but also by demonstrating a far greater willingness to align themselves openly. Seldom before have the Soviets had such an open invitation from a group of Arab states to increase their military and political presence in the Middle East.

Two of the front leaders, Assad and Qaddafi, have taken steps over the past few months to move closer to Moscow out of fear of Israeli, or American, aggression against them in the new cold war atmosphere.

While Assad was attending the Libya summit, he sent his defense minister, Maj. Gen. Mustapha Tlas, to Moscow for a new round of talks. Reports from the Soviet capital said he was expected to arrange even closer military ties with the Soviet Union than already provided for under the treaty of friendship and cooperation the two countries signed a year ago.

Last July, ships of the Soviet and Syrian navies carried out joint exercises off the Syrian coast and Soviet marines practiced a landing during the maneuvers. This was the first time Soviet military units carried out such activities in the Middle East in at least a decade.

They appeared at the time to be partly in response to similar exercises the United States Air Force has been holding here in Egypt as part of its buildup of a Rapid Deployment Force capable of intervening in the Persian Gulf region should Western oil lines be threatened.

Even more noticeable has been the shift of Qaddafi towards a closer relationship with Moscow.

The fiery Libyan leader's conflict with Washington took a dramatic turn in mid-August when American F14 fighters from the 6th Fleet shot down two Libyan Soviet-built SU22 bombers over the Gulf of Sidra, which Libya claims as part of its territorial waters.

After that incident, Qaddafi said Libya had to have a "superpower ally" to protect itself from American imperialism, hinted he might join the Warsaw Pact and threatened to attack U.S. nuclear installations located in countries around the Mediterranean if there were further American attacks on Libyan targets.

Qaddafi's change of tone is particularly noteworthy since, unlike the leaders of Syria or South Yemen, he has heretofore refrained from signing a formal treaty of friendship and cooperation with the Soviets.

However, there are reports in Moscow and the Middle East that he soon may travel to the Soviet capital to sign a treaty, too.

A harbinger of his shift came this past summer when Qaddafi broke with another strict tenet in his relations with all big powers and allowed several visits of Soviet warships to Libyan ports.

Israeli intelligence sources quoted in American news dispatches from Tel Aviv said earlier this month that Qaddafi had also arranged this summer to buy another $5 billion to $10 billion worth of arms from Moscow.

The Soviets have been working for years to build a network of allies and alliances as a solid basis for a greater involvement in the region and presumably a springboard for more aggressive action against American policies and interests here.

After suffering serious setbacks here in Egypt, Sudan, Iraq and Somalia since the early 1970s, they have managed a partial comeback by signing new treaties of friendship and cooperation with Ethiopia, South Yemen and Syria over the past several years.

But getting its allies--disparate and distant from one another--to cooperate with each other or form an alliance has been tough going for Moscow. Late last month, however, Libya and South Yemen, with the mediation of Moscow and several Arab go-betweens, agreed to form a three-way alliance with Ethiopia.

The agreement, reached in the South Yemeni capital of Aden, represents the first instance of a non-Arab African state--Ethiopia--establishing a formal alliance with two Arab ones to combat American policy and allies in the region.

To date, pro-Soviet Arab nations have been particularly reluctant to bring non-Arab ones into their fold, and Ethiopia was not included in the Libya summit this past weekend.

Precisely what the front leaders have in mind for their own organization is still not clear. The final communique said they intended to develop the front into a more effective body by setting up committees to prepare detailed plans of action, holding more regular meetings (this was only the fifth summit) and establishing the "necessary institutions."