By REUTERS
LONDON - A central London avenue near Buckingham Palace was closed in a security alert on Monday on the eve of a visit to Ireland by Britain's Queen Elizabeth and a week before US President Barack Obama visits Britain.In a separate incident, police carried out a controlled explosion to destroy a suspicious bag in a central London street, although it turned out to be harmless, a police spokesman said.Two dead in airstrike on vehicle in Syria's Quneitra region