Nine Zimbabwean opposition activists were charged in connection with a series of fire bombings and with weapons violations Thursday, as the main opposition party denied waging an armed terror campaign and said it was being demonized by the government.

Also Thursday, the South African president was appointed to mediate in a crisis that the southern African nation's neighbors worry will spill across borders.

Lawyer Alec Mmuchadehama told The Associated Press that seven Movement for Democratic Change officials or members were charged with attempted murder in connection with nine petrol bombings this month; one was charged with illegal possession of a firearm and one with possession of explosives without a license.

Mmuchadehama said none of those charged were asked to plead and a hearing was set for Friday to allow them time to consult with lawyers who previously denied access. It was not clear what punishment they faced if convicted.

President Robert Mugabe's government alleges the opposition Movement for Democratic Change is stockpiling weapons and is responsible for the petrol bomb attacks, the latest near the eastern town of Mutare on Wednesday. They said petrol bombs were hurled at two gasoline tankers, but the tankers failed to ignite.

"These tactics are to try and divert attention from themselves," secretary-general Tendai Biti of the Movement for Democratic Change told reporters in Harare. "We are dealing with a desperate regime."

On state television on Wednesday night, police displayed explosives, detonators and two handguns they alleged were found at the home of two arrested opposition officials.

Police raided the party's headquarters in Harare on Wednesday, arresting top opposition leader Morgan Tsvangirai and least 60 officials and staff, Biti said.

Biti described the police allegations of an opposition terror campaign as "crazy," adding "They wanted to create a case that Robert Mugabe would make in Tanzania."

The party had campaigned through peaceful demonstrations and protests for dialogue, reform and free and fair elections.

"Our youths are impatient, they are without jobs, but not withstanding this we have restrained them," Biti said, blaming state agents, police and ruling party militias for an upsurge in violence and a spate of abductions and beatings this month across the country.

"What we are seeing is a low-key but highly intense war against the people," Biti said.

Human Rights Watch researcher Tiseke Kasambala also said Zimbabwe's government was trying to portray the opposition as the main perpetrators of violence.

"We believe the main perpetrators of violence are the government," she said at a news conference in Johannesburg, South Africa, adding her organization had no evidence of who was behind the bomb attacks but that they showed "the violence is spiraling out of control."

Mugabe attended an emergency summit of the 12-nation Southern African Development Community bloc in Tanzania, called by leaders concerned that Zimbabwe's ongoing economic, political and humanitarian crises will further hurt a region already hosting millions of Zimbabwean refugees.

At the summit Thursday, South African President Thabo Mbeki was appointed the president of South Africa to mediate the crisis. The leaders decided "to promote dialogue of the parties in Zimbabwe. There is no replacement to that," said Tanzanian President Jakaya Kikwete, who chaired the meeting and who had flown to Zimbabwe for talks earlier this month.

At a news conference in Harare Thursday, opposition lawmaker Felix Mashu said he and dozens of others arrested at the offices were beaten and kicked by police wielding riot sticks. Tsvangirai was not beaten, and was released after several hours' detention to go to his doctor because he still was suffering dizzy spells from alleged police beatings earlier this month, party officials told reporters. There were fears earlier this month that Tsvangirai's skull had been fractured.

Police denied arresting Tsvangirai on Wednesday.

Mashu said those arrested were taken to the main police Harare police station, where many remained held in cells Thursday and denied access to lawyers.

He said in assaults at the party headquarters police "made us lie on our bellies and beat our backs, buttocks and feet."

Police told state media that they arrested 10 people at the party's headquarters suspected of belonging to underground units the government has called "democratic resistance committees."

The United States said Mugabe was trying to intimidate legitimate political opponents.

In Washington Wednesday, State Department spokesman Tom Casey also urged southern African nations to make clear that Mugabe's actions in the recent past are unacceptable. The U.S. comments echoed statements from the European Union.

Mugabe, 83, is under growing pressure to step down as leader of the country he has ruled since independence in 1980. Tensions are said to be rising in his party over his succession, and the opposition blames him for the country's corruption and acute shortages of food, hard currency and gasoline.