Omicron infections multiplying across U.S. and Europe U.S. COVID cases have risen 50% this month LONDON, Dec 20 (Reuters) - Britain"s cabinet will meet on Monday as pressure grows to slow the spread of the Omicron coronavirus variant, a day after the Netherlands imposed a fourth lockdown and as other European countries consider putting a squeeze on Christmas. Omicron infections are multiplying rapidly across Europe and the United States, doubling every two or three days in London and elsewhere and taking a heavy toll on financial markets which fear the impact on the global economic recovery. The variant was first detected last month in southern Africa and Hong Kong and so far been reported in at least 89 countries. The severity of illness it causes remains unclear. Dutch Prime Minister Mark Rutte announced a shutdown on Saturday, ordering the closure of all but essential stores, as well as restaurants, hairdressers, gyms, museums and other public places from Sunday until at least Jan. 14. read more Britain has reported record levels of COVID-19 cases in recent days. The cabinet was due to meet at 2 p.m. (1400 GMT), local media said. Twelve people in Britain have died with the Omicron variant, Deputy Prime Minister Dominic Raab said on Monday, refusing to rule out a tightening of social restrictions before Christmas. "I just can"t make hard and fast guarantees," he told Times Radio. "In assessing the situation we rely very heavily on the real data coming through and it will take a little bit more time to assess this critical issue of the severity of Omicron." Health minister Sajid Javid said on Sunday the British government was watching the data closely. Any decision to limit how people can celebrate Christmas would come at a high political cost for Prime Minister Boris Johnson, whose authority has been undermined by questions over whether he and his staff broke lockdown rules last year. read more The German government"s scientific advisory panel said on Sunday it was necessary to further limit contact, with data so far showing that boosters alone would not be enough to contain the spread of the virus. The state premier of North Rhine-Westphalia, Hendrik Wuest, did not rule out contact restrictions on people who have been fully vaccinated or had a booster shot. "We should be careful about ruling anything out," he told broadcaster ARD on Monday. Ireland on Friday ordered bars and restaurants to close at 8 p.m. and reduced the capacity in all public events. Italy is also considering new measures to avoid a surge in infections, newspapers reported on Sunday. "ENDLESS HEADWINDS" U.S. stock index futures tumbled more than 1% on Monday, dragged down by concerns about the impact of tighter restrictions on the global economy. "After battling endless headwinds in recent weeks, markets have finally been knocked over as the rapid spread of Omicron finally reaches panic mode," Russ Mould, investment director at AJ Bell, wrote in a client note. European stocks (.STOXX) hit two-week lows and were down 1.49% at 1205 GMT. Shopper numbers across Britain"s high streets fell 2.6% over the Dec. 18-19 weekend versus the previous weekend, researcher Springboard said.[nL1N2T50N3[ "Omicron...remains one of the biggest issues for markets right now and has significantly clouded the outlook moving into year-end," Deutsche Bank analysts said in a note, adding that Manchin"s stance "marks a significant blow for President Biden’s economic agenda". Israel added the United States to its "no-fly" list, citing concerns over the Omicron variant. U.S. infectious disease expert Anthony Fauci said Omicron was "raging through the world" as he urged Americans to get booster shots. Since the start of the month, U.S. COVID cases have risen 50%, according to a Reuters tally. New York state recorded its third straight day of record cases with more than half in New York city, where Mayor Bill de Blasio called for the country to "go on a war footing" to fight Omicron with vaccinations. Booster shots, on top of two-shot vaccinations, appear key to fighting the variant. Moderna Inc (MRNA.O) said on Monday a booster dose of its vaccine seemed to be protective against Omicron in laboratory testing, and that the current version of the shot would remain Moderna’s "first line of defence". read more Thailand is considering reinstating mandatory quarantine for foreign visitors as the health ministry reported the country"s first case of local transmission of the Omicron strain. read more Australia for its part is pushing to ease curbs despite a predicted surge in infections, hoping inoculations will help keep people out of hospital. read more More than 274 million people have been reported to be infected by the coronavirus globally since the first cases were identified in China in December 2019. More than 5.65 million people have died. Interactive graphic tracking global spread of coronavirus: open https://tmsnrt.rs/2FThSv7 in an external browser. Eikon users can click https://apac1.apps.cp.thomsonreuters.com/cms/?navid=1063154666 for a case tracker. Reporting by Reuters bureaux; Writing by Nick Macfie; Editing by Frank Jack Daniel and Mark Heinrich