MANAGUA, NICARAGUA, MARCH 7 -- The Sandinista party newspaper Barricada today described yesterday's street clashes in the city of Masaya between progovernment and opposition followers as "a true popular uprising against the right wing."

But many Masaya citizens put it differently. "The turbas are back," one said.

The turbas, Spanish for "mob," are the civilian shock troops of the eight-year-old Sandinista revolution. Drawn from the most dedicated ranks of the ruling Sandinista National Liberation Front (FSLN), the club-carrying gangs include schoolboys, Army veterans, feminists, factory workers, even elderly mothers who have lost sons in the war against the contra rebels. They were out in force in Masaya yesterday.

The Sandinista party sends turbas to harass, intimidate and overwhelm its numerically smaller political opposition by painting progovernment graffiti, shouting slogans, throwing stones and swinging sticks. Though Nicaraguans are rarely killed in turba attacks, many have been hurt.

The turbas emerged in late 1980. For four years they acted frequently against right-of-center political parties and churches associated with the conservative Roman Catholic leader, Cardinal Miguel Obando y Bravo. After the 1984 elections in which Sandinista President Daniel Ortega was elected, strict state-of-emergency laws were enforced, and activity by the turbas subsided.

Ortega lifted the emergency in January to comply with a regional peace plan, but since then the FSLN has begun mobilizing its militants again to maintain a measure of political control.

Masaya, located 20 miles south of Managua, strongly supported the Sandinistas in their 1978-79 armed insurrection against dictator Anastasio Somoza Debayle. Now, Masaya is known for its strong opposition to the Sandinista military draft and its economic programs.

The opposition, particularly in Masaya, has street fighters as well, and opposition protesters also threw rocks yesterday.

The FSLN is the only party with trained, disciplined gangs who follow orders from higher officials. The turbas usually do not act without approval from some official at the highest level of the party and government.

Normally the party recruits its gangs from unions, block committees and Sandinista youth groups the day before an event and issues precise instructions about the slogans to be used and actions to be taken, rank-and-file Sandinistas said in interviews.

They are often advised not to say that they are closely affiliated with the FSLN, but to describe themselves as spontaneous demonstrators from "the people."

In Masaya, Federico Lopez, the FSLN party chief and in practice the governor of the Masaya region, led several hundred Sandinistas on a chase after about 800 opposition demonstrators, who had gathered for a Women's Day march.

In a midday speech to about 3,000 excited Sandinistas, Lopez first invited them to "confiscate" a movie theatre where the opposition rally had started. The crowd began breaking chairs in the theater, but Lopez changed his mind, and the crowd quickly obeyed his orders to stop.

Several hundred Sandinista men arrived at their party's rally yesterday with wooden clubs that had been issued beforehand, some bearing Sandinista flags.

At one point, one group of turbas discovered some opposition demonstrators hiding in a Catholic church on a sidestreet and banged on the door with their sticks.

Their leader, a Sandinista youth member, spoke briefly with a priest who had come to a window. The leader issued an order to leave the church alone, and the banging quickly ceased.

Recently two American diplomats got a small taste of turba-style tactics.

Sent by the U.S. Embassy to observe a major Sandinista rally Feb. 26 in Managua, they were watching an Interior Ministry contingent file into a plaza when one official in the ranks spotted them and shouted, "Those men are from the American embassy!"

Moments later, the Interior Ministry group broke ranks, surrounded the diplomats and lifted one of them bodily off the ground, knocking off his glasses and roughing him up slightly while chanting anti-American slogans. Then they suddenly put him down, fell back in line and marched on.

The Interior Ministry is in charge of political security and is believed to be, along with the Sandinista party, in charge of the turbas.

Nicaraguans who turn out for turba actions are dedicated to the FSLN. Many are from the poorest families and have been close to the Marxist party since the mid-1970s, when young, bearded Sandinista revolutionaries were widely regarded as heroes in the fight against the unpopular Somoza.

Yesterday, Ramon Gomez, a 36-year-old shoemaker and Sandinista loyalist, was carrying a poster of a widely distributed photograph taken of him in Masaya in 1978 wearing a mask and clutching a contact bomb, fighting alongside the Sandinistas. "This is why I'm here today, repudiating the right-wing," Gomez said proudly, pointing at the picture. But their devotion has also bred intolerance and frequently spawns blanket condemnation of the opposition as being CIA-backed.

Opposition leaders said today that 27 persons were injured yesterday and 11 have not returned to their homes. A prominent leader of the moderate Social Christian Party, Erick Ramirez, was dragged into the street from a house where he was hiding by Sandinistas who tore off his shirt and hit him, his party said.