KATHMANDU (Reuters) - Nepals President has given political parties until Saturday to form a government after Maoist Prime Minister Prachanda resigned in a crisis that has threatened the Himalayan nations fragile new democracy. The Presidents deadline came as the main parties met on Tuesday to try to form a coalition government after former guerrilla leader Prachanda quit because his decision to sack Nepals Army Chief was blocked by President Ram Baran Yadav. Efforts to forge a new government will require bringing together about two dozen parliamentary groups, highlighting the difficulties of alliance-building in one of the worlds poorest nations which is also emerging from a decade-long civil war. Prachanda had fired General Rookmangud Katawal, saying he had undermined the authority of the civilian government, but the decision was opposed by some government allies and the president. The Maoists, the biggest group in parliament with 40pc of seats, have vowed to take to the streets and disrupt parliament to protest against what they say is their ousting by the opposition. The Maoists also boycotted the all-party meet called by its former allies, the Communist Party of Nepal-Unified Marxist Leninist (UML), that is now trying to form a new govt with the support of NC. More than 2,000 Maoist activists marched on the streets of the capital Kathmandu calling for the removal of the Army Chief. If the parties do not meet the Presidents deadline, the interim constitution requires that parliament elect a prime minister. The constitution is unclear on what would happen if no leader was elected and there is fear of a political deadlock. Jhal Nath Khanal, leader of the moderate Communist (UML) party which is likely to lead a new coalition, said efforts were being made to include the Maoists, their former allies. If there is no consensus then we will try for a government by simple majority, Khanal said. The Maoists have said they could consider backing a new government if Army Chief Katawal is removed. The interim parliament, paralysed in the past by the Opposition Nepali Congress (NC) party, on Tuesday saw the out-of-power Maoists take their place. The house had no hope of conducting its business as the largest party in the house stormed the rostrum, raising slogans against the President and condemning his unconstitutional move of reinstating Army Chief Katawal. We demand the revoking of the unconstitutional step and will not allow the house to sit till it is done, the chief of the Maoists parliamentary party, Narayan Kaji Shrestha Prakash, said. Protests by Maoist lawmakers also disrupted proceedings in the national parliament and Maoist spokesman Dinanath Sharma said the protests will escalate unless the President apologises. Thousands of Maoist supporters took to the streets of Nepals capital Tuesday, a day after the leader of the ex-rebels quit as prime minister following a bitter row over the countrys army chief. Prachandas supporters on Tuesday kicked off what they vow will be a massive campaign of civil disobedience. The Maoist protesters chanted slogans including President Resign and Long Live Maoists, under the watch of large numbers of riot police. Police detained dozens of Maoist protesters who tried to march to the high-security presidential palace in the capital on Tuesday, demanding civilian supremacy over the army. We will not let normal proceedings of parliament go ahead until the President corrects his highly unconstitutional and objectionable step of keeping Katawal in office, Maoist spokesman Dinanath Sharma said.