The U.S.-Libyan clash has embarrassed moderate Arabs and drawn predictable, if opposite, responses from Israel and Middle East radicals.

Symptomatic of moderate Arab discomfort today was a carefully noncommittal Egyptian Foreign Ministry statement representing Cairo's first official comment on the three-day-old clash.

"Egypt expresses concern over the deteriorating situation in the Gulf of Sidra and urges both sides to avoid further escalation," the statement said.

President Hosni Mubarak added, "I hope these operations will come to an end" -- as if to suggest, observers said, that the Reagan administration's action could only complicate his already uncomfortable position as the leader of the only Arab country that has signed a peace treaty with Israel.

Egypt, like such other Arab moderates as the Persian Gulf states and Jordan, finds itself pressed by traditional ties of formal Arab solidarity and uneasy over actions by the United States, with which it is politically close.

Israel's endorsement of Washington's actions underlined Egypt's vulnerability at a time when Cairo is seeking to expand its influence in the Arab world without violating its formal peace with the Jewish state.

The complexity of the legal argument about Libya's contested claim that the Gulf of Sidra lies within its territorial waters provided moderate Arab governments with an excuse for not taking a public stand on the issue.

The government-owned newspaper Al Ittihad in the United Arab Emirates expressed "surprise at this silence in Arab capitals regarding the aggression against Libya."

Yet, even radical Arab states privately make no secret of their longstanding exasperation with Col. Muammar Qaddafi, the Libyan leader. In Egypt's case, analysts here pointed out, Mubarak is unlikely to forgive Qaddafi for broadcasting calls for revolt against Mubarak's government during last month's mutiny by police conscripts.

But most moderate Arab governments avoid siding openly with the use of American force. This is partly because of what many Arabs, rightly or wrongly, consider U.S. policy errors in recent years that are considered to have weakened them.

No more than the most radical Arab leader can Mubarak, King Hussein of Jordan, or Saudi King Fahd endorse an attack on any Arab country by a foreign government, especially a superpower, without further undermining his political position at home.

Mubarak said as much last December, after a series of policy traumas occasioned by the use of military power first by Israel against the Palestine Liberation Organization headquarters in Tunisia, then by the United States in seizing an Egyptian airliner carrying Palestinian hijackers involved in the Achille Lauro cruise ship takeover.

Even today Mubarak found it politically expedient to allow the left-wing National Unionist Progressive Party to condemn "U.S. aggression" as "part of a Zionist-American plot aimed at subjugating the Arab nation." It added, "In these trying times for the Arab nation, we announce our complete material and moral support for the Libyan people."

Privately, many moderate Arabs say they wished the Reagan administration would either take decisive action to overthrow Qaddafi or leave him alone. Many Arab and European analysts have long argued that the best way to deal with Qaddafi is to ignore him, since he thrives on playing Arab David to the American Goliath. As in January, when Washington applied economic sanctions, Qaddafi is again playing the underdog, currying support here and in the Arab world.

Even after the present crisis subsides, analysts say, they are concerned that Qaddafi's threats against American interests could add further motivation to an already serious cycle of violence.

Years ago, Syria decided that it could attract financial aid and diplomatic support from its normally unenthusiastic fellow Arabs by provoking a perceived showdown with Israel or the United States.

Some moderate Arabs argue that the Reagan administration finds Libya a convenient, if geopolitically marginal, regime to hold responsible for its own setbacks in the Middle East. Syria, they argue, is a more formidable foe of U.S. policy, but is so strategically located and so obviously backed by Moscow that Washington is reluctant to use force against it.

As if to make this point indirectly, the Fatah Revolutionary Council, a breakaway Palestinian faction run by terrorist Sabry Banna, also known as Abu Nidal, warned in Syria yesterday that "anything American has become, from now on, a target for our revolutionaries."

The Reagan administration justified its anti-Qaddafi drive this winter by accusing Libya of organizing the Vienna and Rome airport attacks in December. They were said to have been carried out by Abu Nidal's organization.