Sudan and South Sudan pledged to cease hostilities along their disputed oil-rich border Saturday but stopped short of actually signing an agreement, officials said.

The verbal agreement came as the latest round of talks closed in the Ethiopian capital ahead of celebrations Monday to mark one year of independence for South Sudan.

The speaker of the legislature in Sudan's war-torn South Kordofan state has been killed in an ambush along with seven other people, official media reported, as rebels in the region denied any involvement.

Ibrahim Balandiya died in the attack on Friday in Habila district of the state's north, the official SUNA news agency reported.

Sudanese police on Friday "attacked" with tear gas and rubber bullets as demonstrators gathered at mosques for weekly anti-regime protests sparked by inflation, a rights group said.

"Still large numbers of police forces are surrounding the central mosques," said an official of the Organization for Defense of Rights and Freedoms, representing political, media, trade union and other activists promoting human rights.

Sudan's opposition parties have pledged to step up anti-regime protests and press for a multi-party system, their alliance said on Thursday.

About 17 political parties signed the charter on Wednesday, along with non-governmental organizations and individuals, said Farouk Abu Issa, head of the opposition coalition.

About 1,000 people were detained and hundreds injured -- many by tear gas -- during anti-regime protests on Friday in Sudan, an activist group said on Saturday's anniversary of President Omar al-Bashir's coup.

The information minister called the protesters "rioters" who threaten the country's stability.

More than 100 Sudanese lawyers in black legal gowns demonstrated on Thursday in defense of free speech, Agence France Presse reported, on the 13th day of unprecedented public protests.

"Demonstration is a constitutional right," said one of their banners, while another declared "Freedom of expression is a legal right."

Sudanese demonstrators staged on Saturday small-scale protests sparked by rising prices, witnesses said, the day after unrest engulfed the capital Khartoum and cities across the country.

"We will not be governed by a dictatorship!" demonstrators in the eastern town of Gedaref shouted, according to two witnesses.

South Sudan must stop arbitrary arrests and improve the "dire" conditions in its prisons, where a third of inmates are held on remand and some without having been charged, Human Rights Watch said Friday.

"Flawed processes, unlawful detentions, and dire conditions in South Sudan's prisons reflect the urgent need to improve the new nation's fledgling justice system," the New York-based group said in a report.

University students staged anti-regime protests in Khartoum for the fifth straight day on Wednesday, with Sudanese riot police using tear gas and batons to disperse them, witnesses said.

The demonstrations, which began on Saturday and have spread to different parts of the capital, come amid a rapidly deteriorating economic situation that has forced the government to make drastic spending cuts and driven up the cost of living.

Sudanese riot police on Sunday attacked a Khartoum student demonstration against high food prices, firing tear gas and beating some of the protesters with batons, Agence France Presse reported.

At around midday (0900 GMT), hundreds of students emerged from the University of Khartoum campus, located in the city center, adjacent to the Blue Nile river, chanting slogans including: "We want lower food prices!"