The Cuban flag will be raised at 1430 GMT Monday over an embassy in Washington, ending 54 years of a bitter diplomatic boycott, dpa reported. The flag-raising at Cuba's current Interests Section building on Washington's tony Embassy Row will symbolize the restoration of US-Cuba diplomatic relations. In Havana, the US mission will begin operating Monday as an embassy, but a formal flag-raising will only take place later this summer during a visit by Secretary of State John Kerry. US President Barack Obama and Cuban leader Raul Castro took the world by surprise in December, opening the door to restoring relations with a prisoner exchange - the result of 18 months of secret talks led by the Vatican.