Top aides to Iranian opposition leader Ayatollah Ruhollah Khomeini said today a provisional Islamic government would be announced "within a few days, if not sooner," and that if the current government does not step aside immediately street violence is inevitable.

Meanwhile, Prime Minister Shahpour Bakhtiar reiterated that he would not allow Khomeini to set up a provisional government in Iran, and said that if the ayatollah "passes from words to action, there will be trouble."

Nevertheless, as the saber-rattling statements were being made, the two sides continued to negotiate secretly in hopes of reaching a political solution and to avoid further bloodshed.

In an obvious attempt to intensify the pressure on Bakhtiar's beleaguered government, Khomeini's aides said that a "very important announcement" was to be made this afternoon, resulting in a flurry of speculation that the long-awaited provisional government was about to be created.

When it came time for the announcement to be made, however, Ibrahim Yazdi, Khomeini's aide, said it would be postponed for a few days.

In spite of the sense of urgency the Khomeini strategists attempted to create and in spite of the Shiite Moslem leader's angry threat to force the capitulation of Bakhtiar, behind-the-scenes negotiations with Iranian Army generals continued and Khomeini's negotiators continued to talk with Bakhtiar.

A source close to the negotiations confirmed that Mehdi Bazargan, the senior statesman of Iran's revolutionary politics, met with Bakhtiar as recently as Saturday in an attempt to bring the prime minister and the ayatollah together.

Bazargan, a senior adviser to Mohammed Mossadegh in 1951 when Mossadegh briefly displaced Shah Mohammad Reza Pahlavi before being overthrown, has long had the trust of both both Khomeini and Bakhtiar. Bazargan was a close friend of Bakhtiar in the opposition National Front before moving to the Iran Freedom Movement.

Sources close to the negotiations stressed, however, that "there is nothing to compromise about," and that the talks are intended simply to persuade the prime minister to quit.

Another purpose of the negotiations appears to be to buy time for the Khomeini aides, including Bazargan, to continue talks with military leaders that could lead to a Khomeini takeover of the government without intervention by the army.

Sources close to the talks said some army commanders have expressed a willingness to accept Khomeini's proposed Islamic republic, but they are not key generals at the top of the military establishment.

By marking time on the formation of a new government, Khomeini sources said, the ayatollah is not only giving his negotiators more time to talk with the generals, but is extending the time for defections from within the army ranks.

Reports persist of mutinies and desertions among enlisted men, with more than half the Iranian naval academy's cadets said to have deserted.

According to diplomatic sources, Bazargan has been negotiating with Gen. Abbas Gharabaghi, the Iranian chief of staff, in an effort to reach an agreement between the military and Khomeini on Iran's future government.

Bakhtiar, who still has the firm support of the generals, is said to have approved of the negotiations.

One motive of the Khomeini camp in delaying announcement of the provisional Islamic government also is to steadily wean the military away from its longstanding loyalty to the shah, poitical analysts said.

They said that the longer the status quo conitinues, the greater the chance that senior generals will realize that they do not need the shah and that the monarchy can be replaced by a republic.

Informed diplomatic sources confirmed that top military commanders previously considered loyalist hardliners are becoming less pro-shah. They still are a long way from the Khomeini position, however, and some of them are growing impatient with the continuing political and economic chaos, the sources said.

Some senior commanders have indicated willingness to give Bakhtiar just a few more weeks before taking over themselves, one source said.

They are said to feel confident to the point of cockiness that they can restore order and run the country, even if this required mass killings.

Even so, diplomats doubt that the army could succeed, noting the desertions and breakdown in discipline that have already afflicted the armed forces.

For the past two days, more than 1,000 relatives of arrested servicemen have staged street demonstrations in Tehran to demand their release. Many of those arrested appear to have been air force personnel.

About 70 families staged a sit-in at the Justice Ministry today to protest the arrests. One woman said that her husband, an air force technician, had been arrested by military authorities along with about 800 other servicemen for taking part in a pro-Khomeini demonstration recently at Shahrokhi air base near Hamadan in western Iran. She said about 3,000 air force personnel had been in the demonstration.

Meanwhile, the government, continuing to lobby for public support, arrested two more former Cabinet ministers. They joined about 30 other former officials and prominent businessmen imprisoned under Article 5 of the martial law regulations providing for the arrest of anyone causing "public discontent."

In addition, the government accused the major of Tehran, Javad Shahrestani, of corruption while he was transport minister under a previous government.

Shahrestani yesterday submitted his resignation as mayor to Khomeini, then asked the ayatollah to reappoint him as "Khomeini's mayor." The ayatollah said he would think about it.