MUMBAI/ NEW DELHI, Dec 30 (Reuters) - Indian authorities started to impose stringent rules on Thursday to prevent mass gatherings at new year"s parties and public venues to combat a spike in COVID-19 infections, even as top leaders led large political rallies. Night curfews have been imposed in all major cities and restaurants ordered to limit customers. However, Prime Minister Narendra Modi and Home Minister Amit Shah presided over public rallies in northern states with footage from the events showing thousands of people gathered in open grounds to hear their speeches. Last week an Indian court urged Modi"s government to suspend political rallies and election campaigns in poll-bound states amid the rising number of Omicron cases, a variant of COVID-19. Elections to the state assembly in Uttar Pradesh, home to over 220 million people, is a key battleground for Modi and opposition parties because of its size and because the performance of political parties there will be a barometer for the 2024 national elections. Final dates for polls are yet to declared but all political parties have launched their campaigns, disregarding the social distancing norms. The country reported 13,154 new COVID-19 cases and 268 deaths in the last 24 hours, the federal health ministry said, with urban centres reporting a big jump. Cases of infection by the Omicron variant rose to 961 across India. Police in the financial capital Mumbai prohibited public gatherings of five or more residents until Jan. 7 as it recorded a sharp jump in cases with 2,510 infections, the highest daily increase since May, local authorities said. "It is being seen that social gatherings are going on in an unrestricted manner with people flouting all social distancing norms... we are trying our best to control the spread of the virus," said Rajesh Tope, the health minister of the western state of Maharashtra of which Mumbai is the capital. Tope said the next 48 hours were critical for authorities to prevent an escalation of fresh COVID-19 cases. While government in capital New Delhi closed cinemas, schools and gyms, state leader Arvind Kejriwal on Thursday held a public rally to celebrate victory in local polls in neighbouring Chandigarh city. An Indian newspaper, Mint, quoted Paul Kattuman, professor at the Judge Business School at the University of Cambridge which has developed a COVID-19 India tracker stating that new infections will begin to rise in a few days, possibly this week. "It is likely that India will see a period of explosive growth in daily cases and that the intense growth phase will be relatively short," said Kattuman. India accelerated vaccine distribution by approving Merck"s COVID-19 pill and two more vaccines for emergency use. Asia"s third-largest economy has already said it will allow COVID-19 booster shots for some of its population. The emergency approvals come at a time measures are being taken to ramp up oxygen supplies and hospital beds. But an ongoing strike by thousands of junior doctors has added pressure on the fragile health infrastructure. "We are continuing with the agitation," said Dr Manish, President of the Federation of Resident Doctors" Association India, who only uses one name. "If (COVID-19) cases are rising, then how is the government planning to deal with the situation without these doctors in the hospitals?"