Rival political camps in Macedonia staged a third day of protests Tuesday as the embattled prime minister and the opposition leader prepared to hold talks to try to end the crisis.

About 150 opposition supporters rallied outside the main government building in Skopje to press their demands that Prime Minister Nikola Gruevski step down.

The United States on Monday voiced its concerns over a political crisis in Macedonia and called on the government to probe opposition claims of corruption.

"We remain in close consultation with the Macedonian government and with political leaders to convey our concerns about the current political crisis," the State Department's press office director Jeff Rathke told reporters.

Some 30,000 supporters of conservative Macedonian Prime Minister Nikola Gruevski gathered in downtown Skopje on Monday, a day after thousands of opposition demonstrators marched through the capital demanding that the premier resign.

The pro-Gruevski rally was being held outside the parliament building, some two kilometers (1.5 miles) away from where hundreds of opposition supporters were camping out in front of government offices, according to AFP journalists.

Macedonian opposition supporters set up a protest camp outside the offices of embattled Prime Minister Nikola Gruevski as thousands of his supporters were expected to turn out for a counter rally on Monday night.

More than 20,000 opposition protesters marched through the capital Skopje on Sunday to demand that Gruevski step down, accusing him of corruption, mass wiretapping and of fomenting ethnic tensions to hang onto power.

Macedonia's opposition vowed to continue street protests after 20,000 people marched through the capital Skopje on Sunday demanding that the country's embattled Prime Minister Nikola Gruevski step down.

With the small Balkan country divided by a deep political crisis -- and still in shock after last weekend's battle with ethnic Albanian gunmen in which 18 died -- Gruevski's supporters are to march on Monday after Sunday's big show of force by the opposition.

Russian Foreign Minister Sergei Lavrov said Friday Moscow was worried about the stability of Macedonia and the whole Balkans region after after recent deadly violence there.

"The latest events in Macedonia are very worrying... as well as terrorist tendencies emerging in the Balkans," Lavrov told reporters in the Serbian capital.

Macedonia's interior and transport ministers as well as the country's intelligence chief resigned Tuesday after deadly violence that pitted ethnic Albanian rebels against Macedonian police, a government spokesman said.

"Interior Minister Gordana Jankuloska, Transport Minister Mile Janakieski as well as the director of DBK Saso Mijalkov presented their resignations," a government spokesman told Agence France Presse. "Prime Minister Nikola Gruevski accepted their resignations."

Kosovo's Prime Minister Isa Mustafa said Tuesday his country would help prevent a regional escalation of the recent unrest in neighboring Macedonia that left 22 people dead and dozens of homes destroyed.

"Kosovo is interested in a tight cooperation between its police and the police of Macedonia in clearing up the circumstances that led to the unacceptable and unjustifiable situation," he told journalists during an official visit to Slovenia.

Thirty alleged gunmen were charged Monday with terror offenses after a bloody shootout with Macedonian police which left 22 dead, including eight police officers, and dozens of homes destroyed in a town close to the border with Kosovo.

The clashes in Kumanovo at the weekend were the worst in Macedonia for 14 years, and raised fears of a fresh conflict similar to the country's 2001 ethnic conflict.

The EU said it was "deeply concerned" over events unfolding in crisis-hit Macedonia following deadly clashes that killed at least eight police officers and 14 unidentified gunmen.

"Any further escalation must be avoided, not the least in the interest of the overall stability in the country," EU enlargement commissioner Johannes Hahn said in a statement late Saturday responding to the eruption of violence.