Anti-shah demonstrators burned several military vehicles and set bonfires in the streets today in the most serious mob violence since major rioting in the capital early last month.

The escalation of disturbances in Tehran cam as oil production plunged to about 700,000 barrels, slightly more than 10 percent of expected output this time of year. Opposition sources attributed the sharp drop-from nearly 4 million barrels a day last week-to mass resignations by oil workers in response to strong-arm tactics by martial law authorities trying to force strikers back to work.

According to oil industry sources, Iranian crude exports dropped to zero today because of the disruptions. The halt in export operations means a loss of more than $70 million a day in forfeited oil revenue, they said.

The continued turmoil in the capital, which seemed to take on an increasingly antiforeign tone, remained at a much smaller scale than the destructive riots of Nov. 5 that led to installation of the present military-led government. But it nevertheless dramatized the government's inability-or unwillingness-to get enough troops into the streets to carry its thereat of using tough military action under martial law to guarantee order.

Political opposition sources said at least nine persons were killed in Tehran when troops opened fire to disperse small mobs in different parts of the city. Martial law authorties said, however, that the capital's victims numbered only two.

A spokesman fot the opposition National Front reported 13 killed in Tabriz, in the northwestern corner of the country, during similar protests. He said a large protest march in the Shiite Moslem shrine city of Mashad, in the northeast, sparked a demonstration inside the local jail during which two prisoners were killed.

The inmates than went on a rampage and set fire to the prison, he said. Authorities reportedly made no attempt to put out the blaze and it contiuned to burn into the night.

The day's victims in Tehran included a 28-year-old professor who was shot when he ventured out onto a balcony of the Ministry of Science ahd Higher Education, where about 80 academicians were staging a sit-in to demand the reopening of universities.

Accounts of the shooting conflicted. Some professors at the scene said their colleague was killed when a soldier in a cintingent of troops outside the building fired a single round from the street. Others said the shots came from a building opposite the ministry where the secret polic, SAVAK, is reported to maintain an office.

Elsewhere in the capital, mobs of mostly young protesters set up burning barricades across a number of streets, adding to the usual traffic chaos. The crowds gathered around the barricades and chanted slogans against Shah Mohammad Reza Pahlavi until troops arrived to disperse them.

The demonstrators scribbled anti- shah messages on scraps of paper and stuck them to car windshields, antennas and nearby buildings. Many office workers threw sheets of paper out their windows to the crowds below.

The "Felt-Tip Pen Brigade" also engaged in a version of a Chinese wall poster campaign, writing bits of news claiming inflated death tolls and reporting various incidents. A message in English posted near the U.S. Embassy said, "Don't get killed. Leave the country before Feb. 1."

Several army trucks and jeeps were firebombed in fifferent parts of the city. In one incident, youths sneaked into jeeps that had been temporarily left by soldiers and drove away in them.

A National Front spokesman said the most serious incident occurred in front of the National Iranian Oil Co. building in central Tehran when, he said, four soldiers disobeyed orders to fire on demonstrators, shot their commander instead, and ran away. There was no independent confirmation of the report.

In another incident, youths stopped a beer truck, threw its bottles and cans on the street, and set the truck on fire, before troops could arrive. The windows of several banks were broken, although protesters mostly confined their activites to bonfires.

Most shops in affected districts closed as the mob violence spread and traffice thinned out considerably. By early evening many downtown streets were deserted hours before the nightly 9 p.m. curfew.

In southern Iran, the latest drop in oil output threatens to aggravate shortages of kerosene and diesel fuel used for heating and industrial purposes and could bring on a gasoline crisis, industry sources said. Iran, normally the world's second leading oil exporter, already has been forced to import some refined petroleum products from saudi arabia and kuwait.

According to opposition sources, the sharp downturn in oil production is the result of the resignation of more the 3,000 oil workers in the last few days and renewed walkouts by thousands of others. The action was to protest efforts by local martial law authorities acting on orders of the prime minister, Gen. Gholan Reza Azhari, to break a three-week-old strike by arresting strikers and trying them in military courts under the 1957 Oil Industry Sabotage Act.

Iran normally requires 600,000 to 700,000 barrells of oil a day to meet domestic consumption. But the ability to satisfy those internal needs also depends on availability of different grades of crude produced by separate oil fields and operation of the country's refineries.

Therefore, according to oil industry sources, Iran could continue to produce at the level of domestic consumption and still face severe shortage of petroleum products.

Even if production were to shoot up imeediately to the normally expected levesl for this time of year-6.5 million barrels a day-and major refineries were to resume total operations, the output of much-needed kerosene and diesel fuel would still fail to meet current demand, the sources said. This is because the peak winter consumption normally is met with the help of stocks built up during the summer, but which already have been largely depleted.