HARARE, Zimbabwe – Talks aimed at salvaging Zimbabwe's power-sharing agreement resumed Tuesday with no breakthrough but more negotiations were expected this week, President Robert Mugabe and his political rival Morgan Tsvangirai said.

“We have not finished,” Mugabe said as he left the Rainbow Towers Hotel in Harare late Tuesday after talks with Tsvangirai. “We have covered some ground.”

South African President Thabo Mbeki was mediating the talks.

Tsvangirai left the hotel earlier, saying no conclusion had been reached and negotiations would continue Wednesday.

Also Tuesday, riot police broke up a student demonstration held outside the legislature as the new opposition-dominated parliament gathered inside for its first working session.

Witnesses saw at least three students bundled into a police van. A number of others were injured in a scuffle and had to be helped to a clinic. Police comment was not immediately available.

Mbeki brokered a Sept. 15 deal between Mugabe and Tsvangirai to form a unity government. The opposition narrowly won March parliamentary elections.

But over the weekend, Mugabe said his party would control all key ministries, prompting Tsvangirai to threaten to quit negotiations.

While politicians bicker about Zimbabwe's government, half the population – 5.1 million people – faces starvation, two-thirds of children are out of school, and water shortages have led to deadly cholera outbreaks in three parts of the country, according to aid agencies.

Mugabe's chief negotiator, Justice Minister Patrick Chinamasa, said on state radio that the nation has been “drifting” since the elections without a full government.

The new 210-seat legislature that met Tuesday is the first controlled by the opposition since Zimbabwe gained independence in 1980.

Inside, lawmakers heckled each other during a lively debate on a speech given by Mugabe at Parliament's official opening ceremonies in August.

Lawmakers will reconvene Wednesday, when legislation will be introduced that is necessary for the formation of the new government. The constitution needs to be changed to create the post of prime minister, which is supposed to be filled by Tsvangirai.

Mugabe's party and the opposition have been unable to agree on the allocation of Cabinet posts. The power-sharing deal calls for the opposition to control 16 Cabinet seats and Mugabe's party 15.

Mugabe's unilateral move to take control of key government ministries has been condemned by the European Union and the United States. An official list published Saturday gave Mugabe's party portfolios for defense, home and foreign affairs, justice, mining and land, among others. The list assigned the opposition with minor ministries, such as constitutional affairs and water management.

Tsvangirai balked at the list, telling thousands of supporters at a rally Sunday: “That is not power sharing, it is power grabbing.”

He said Zimbabweans were prepared to “suffer some more” to get a more equitable agreement.

U.S. State Department spokesman Sean McCormack said Tuesday that Mugabe had “overstepped the bounds of the agreement” by claiming key ministries.

“We would like to see the implementation of that original agreement get back on track,” he said. “And, of course, any implementation solution has to be one that is acceptable to the MDC and Mr. Tsvangirai.” The MDC is the Movement for Democratic Change, Tsvangirai's party.

Zimbabwe is in economic meltdown, with official inflation given as 231 million percent, by far the highest in the world. The nation faces chronic shortages of gasoline, food, all basic goods, cash and water and electricity.