BRASILIA, Jan 18 (Reuters) - Brazil reported a record 137,103 new cases of the novel coronavirus in the past 24 hours as the Omicron variant spreadsin the South American country, the Health Ministry said on Tuesday. The number of deaths has also risen, to 351 reported on Tuesday, the highest number since mid-November. With the highly transmissible Omicron becoming the dominant variant in the country, new cases have soared above the previous daily record of 115,228 on June 23 last year. Brazil has now registered 23,211,894 cases since the pandemic began in 2020, while the official death toll has risen to 621,517, according to ministry data. Brazil has the world"s third highest death toll from COVID-19 after the United States and Russia, according to Reuters calculations. The spread of Omicron has filled hospitals again, leading authorities to provide more beds and mobilize more medical staff, though the variant appears to be less lethal than previous ones. Almost 70% of Brazilians are fully vaccinated, and Brazil this week started vaccinating children aged 5-11 years, despite opposition from vaccine-skeptic President Jair Bolsonaro.