Pro-shah demonstrators staged rallies in cities and towns across Iran today, apparently signaling a major government effort to regain the initative from Iran's powerful religious and political opposition after massive anti-shah protests.

One of the major centers of today's pro-shah demonstrations, protected by martial law forces, was Isfahan, which has been the scene of fluctuating cycles of violence over the last three days as protesters and troops clashed.

There were reports of several deaths today and doctors at one Isfahan hospital estimated that between 30 and 50 persons had been killed by troops during the three days. The government has admitted an overall toll of nine while opposition sources said it numbers in the hundreds.

Witnesses and officials denied yesterday's reports of firing from helicopter gunships, clashes between proand anti-shah demonstrators and the sacking of the headquarters of the secret police, all of which erroneously depicted a situation of near-insurrection in Isfahan.

The pro-shah demonstrations which I witnessed yesterday were rowdy but resulted in no casualties. However, in other parts of town and outlying areas troops attacked unarmed anti-shah demonstrators, hundreds of whom were hospitalized, according to reports from Isfahan.

One diplomat told the Associated Press: "Tuesday was a day of bitter brutality rather than shooting. Most if not all of the deaths occurred in the rioting Monday night."

Announcing the new pro-shah demonstrations today, the official Iranian radio said "hundreds of thousands" of marchers took part in at least eight cities and towns, including Isfahan and Tehran. Witnesses in Isfahan said, however, that only about 1,000 took part in the demonstration there and that the march could not have taken place without the protection of the army.

Other cities in which such demonstrations were reported included Mashad, Iran's third largest city and a stronghold of the Shiite Moslem opposition in northeastern Iran, and the industrial city of Arak in the west.

Reports from Isfahan said many motorists were forced to join the demonstration at thr risk of being beaten up or having their car windshield smashed.

Western officials said the martial law authorities and the Ministry of Agriculture brought in farmers and villagers from the surrounding countryside for the demonstration. Soldiers and the pro-shah civilians rolled through the city in buses and army trucks, exhorting the local populace to join their shouts of "Javid Shah" (Long live the shah). Some residents did, witnesses said, but not many. Wire services reported that some who refused were beaten.

The government apparently hopes that a snowballing effect will emerge to stem the tide of burgeoning anti-shah portests.

Political observers said the shah's military government possibly could hope to rally support by playing on public dissatisfaction. There does seem to be growing anxiety over the political strikes, notably in the oil industry, that have brough Iran's once booming economy to a grinding halt.

It appears doubtful, however, that the government would be able to reverse the kind of opposition sentiment that drew millions of Iranians into the streets for anti-shah marches this week. The latest pro-shah demonstrations seemed pale by comparison and undoubtedly could not be held in the present political climate without army protection.

In fact, some diplomats feel, rather than help to restore stability to the country, the pro-shah rallies create the conditions for more and perhaps greater bloodshed by turning civilians against each other.

Isfahan has been a powder keg ever since Monday night when anti-shah demonstrators toppled four statues of the monarch and burned or damaged several banks, theaters and government offices. Troops fired on the demonstrators, beginning the cycles of bloodshed that continued through yesterday and today in sporadic waves.

Meanwhile, oil production dipped again as workers in Abadan voted to continue their 10-day-old strike, according to oil industry sources.

Iran is already seeking to purchase kerosene and diesel fuel on the international market and sources said the country, the world's second largest oil exporter in normal times, may soon be forced to import gasoline.

Industry officials said that production was down to 1.1 million barrels today, less than 20 percent of normal. UPI reported from Isfahan:

Most of today's pro-shah demonstrators were farmers, but there were also many who wore expensive clothing and had neat haircuts who were said by witnesses to be agents of SAVAK, Iran's feared secret police.

All nine operating rooms at the Soraya Hospital were crammed with wounded. Doctors said a man who died while reporters were there was one of 11 persons shot as they lined up to donate blood to persons injured earlier.

"The troops saw people lined up to give blood and opened fire," one doctor said. "An hour later they came back with axes to do in people who hadn't learned their lesson and left." CAPTION: Picture 1, Exiled Ayatollah Ruhollah Khomeini leaves tent after prayers in suburban Paris.; Picture 2, Iranians wait at a Tehran filling station for kerosene, the staple fuel made scarce by strikes. AP