At least 16 persons were killed today in Zimbabwe's worst factional violence since the nation became independent seven months ago.

Residents of Bulawayo, the southwestern provincial capital where the clashes are taking place, said thousands of blacks were fleeing the surrounding African townships because of the battles between former guerrillas loyal to Prime Minister Robert Mugabe and Home Affairs Minister Joshua Nkomo.

Bulawayo police spokesman Piers Winter said 16 persons, including both "armed dissidents" and civilians, had been killed and about 200 had been injured. Firing went on all day in Entumbane township where former guerrillas of the two rival factions have been relocated. The situation was "still highly charged" and was not under control by nightfall, the spokesman said.

"Actual casualty figures will probably be much higher, but we are not going to be able to find out until the firing stops," a police source said. A number of civilians were caught in cross fire in the townships.

Most Bulawayo factories and stores closed early today, and trains and bus services were sharply curtailed. An overnight curfew has been ordered.

In a nationwide radio and television speech tonight, Mugabe said he had ordered police, Army and Air Force reinforcements to Bulawayo, 250 miles southwest of the capital.

Although he appealed to both sides to follow his policy of reconciliation after the bitter seven-year independence struggle, he was sharply critical of Nkomo's Zimbabwe African People's Union (ZAPU) party and the guerrillas loyal to it.

The two leaders, who headed rival guerrilla armies during the war, have joined in a coalition government that is rapidly fraying.

Describing the "grave situation," he said, "murder, arson, robbery, assault, intimidation and general lawlessness have been perpetrated by misguided and politically motivated armed hooligans and malcontents."

"Unruly ZAPU mobs," Mugabe said, tried to disrupt a rally at which several ministers from his Zimbabwe African National Union (ZANU) spoke. Later, he added, forces loyal to Nkomo began "shelling and firing" on the quarters of Mugabe's former army.

Since then, he said, "armed bands have roamed the area."

The prime minister said the "hooligans" and "malcontents" were seeking to overthrow his government but they were "up for a rude shock."

He ordered the commanders of both guerrilla armies to Bulawayo to defuse the situation and told party leaders to restrain their followers.

That could prove difficult, however, since the violence was linked to a series of inflammatory speeches made by several Mugabe ministers during the weekend in Bulawayo, the stronghold of Nkomo's party.

After the clash at yesterday's rally, Finance Minister Enos Nkala said, "from today [Nkomo's party] has declared itself the enemy of ZANU." He called for a "general mobilization" of party supporters.

The time has come for the party "to flex its muscles," he said, "to challenge the Patriotic Front on its home ground. If it means a few blows, we shall deliver them."

The outspoken minister who has previously made fiery speeches only to be put down by the more moderate Mugabe, threatened to resign if the prime minister does not take action against Nkomo's forces.

Manpower Minister Edgar Tekere, who is on trial for murder in Salisbury, added to the heated debate today when he announced his support for Nkala and castigated Nkomo's forces for not fighting during the seven-year war to gain black-majority rule.

"Nkomi is in the government by charity," Tekere said. "We don't need him."

Tekere made the remarks to an impromptu press conference outside the courtroom after appearing on the stand for the first time in his trial. He and seven of his bodyguards are accused of killing a white farmer and the attempted murder of several soldiers outside Salisbury in August.

British defense attorney Louis Blom-Cooper spent most of the day having Tekere provide the motivation for a "military operation" the defendants carried out on a farm 13 miles west of Salisbury during which Gerald William Adams, 68, was killed.

The incident occurred the day after Tekere, who is also the number three official in Mugabe's party, and several other senior officials attended a party on the farm during which a soldier fired a burst of automatic rifle fire in the direction of the guests.

Tekere sought to implicate Mugabe in his defense, saying he told the prime minister about the incident the next morning and then added: "I don't think we can take this kind of operation so I'm going back for a cleanup operation." w

"The prime minister didn't object. He didn't say don't do it," Tekere testified.

Tekere's main line of defense is based on a 1975 law passed by the old white-minority government that absolves from prosecution any official or his aides for any act "whatsoever" carried out "in good faith" to suppress terrorism.

He also heatedly denied police allegations that he was under the influence of alcohol or drugs later that night when he visited a police station.

"I have never taken drugs," he said and added in one of many references to his senior position, "I shouldn't ever have to answer a question like that."

Tekere also referred to the "hostility" between Mugabe's and Nkomo's parties dating back to the 1963 split-off of Nkomo's group.

"We were throwing stones at each other. Now this is the day of bullets, not stones."