Tens of thousands Nepal's Maoist former rebels surrounded the principal government secretariat in Kathmandu on Thursday to pressure the government to debate presidential authority and agree on forming a new government under their leadership.

Maoist lawmaker Chandra Bahadur Thapa said the Maoists plan to mobilize as many as 300,000 supporters as the day progresses to picket the principal secretariat known as Singha Durbar that houses the Prime Minister's Office and more than a dozen ministries.

Clashes erupted briefly between Maoist supporters and security personnel at the southern gate of Singha Durbar after some Maoist supporters tried to step into an area where the government has prohibited protests.

Local television channels reported that police fired 10 rounds of tear gas shells to take control of the situation.

There were no fatalities in the clashes, but at least four dozen people, including seven Maoist lawmakers and three security personnel, sustained minor injuries, according to a leading local news portal, nagariknews.com.

The Maoist supporters started marching toward the secretariat complex from 8 a.m. in a bid to bring official government work to a standstill by preventing government officials from entering the complex.

The rallies being taken from eight different locations in Kathmandu are being led by top Maoist leaders, including Chairman Prachanda.

But government secretaries and ministers sneaked into the complex as early as 6 a.m., hours before the 10 a.m. normal starting time.

Kathmandu chief administrator Bhola Siwakoti said about 3,000 security personnel of the Nepal Police and the Armed Police Force have been deployed to secure the principal secretariat and prevent violence.

"The security personnel have been instructed to exercise maximum restraint as long as the Maoist protest is peaceful," Siwakoti told Kyodo News. "So far, the protest is peaceful."

Maoist lawmaker Dev Gurung said the Maoists have no intention of engaging in violence.

"We will picket Singha Durbar peacefully. Our cadres will spend the day around the secretariat singing, dancing and sloganeering against the president and government," he said.

They have announced they will lay siege on the principal secretariat Friday as well.

The Maoists, who began initial protests in May, resumed their action last week after a monthlong suspension from mid-September for national festivals.

They are protesting President Ram Baran Yadav's May 3 decision to countermand Prachanda's decision to sack the country's then army chief for defying government directives.

This led to Prachanda's resignation as prime minister on May 4.

The Maoists, who have termed the president's step unconstitutional, are demanding that coalition parties agree to debate the presidential move in parliament and are also demanding the current government step down for formation of a "national unity government" under Maoist leadership.

Currently ruling parties have rejected both demands.

Nepal's Maoists fought a decade-long insurgency until 2006 when they joined a peace process.

They were elected as the largest party in last year's special assembly election and their leader Prachanda led a coalition government for nine months until resigning in May.

The protests have hampered key tasks of the assembly, including integration and rehabilitation of more than 19,000 Maoist fighters currently corralled in U.N.-monitored camps and drafting a new constitution.

They have also prevented parliament from passing a full budget bill, which led to a stoppage of salary release to government ministers and the Armed Police Force.

Finance Minister Surendra Pandey has warned the government will be forced to stop salary payments to civil servants and parliamentarians if the bill is not passed soon.