Queen arrives in Ireland after bomb defused near Dublin******

DUBLIN, May 17 (agencies): Queen Elizabeth II arrived in the Republic of Ireland Tuesday, wearing the emerald green of her hosts as she started the first visit by a British monarch in a century. The sovereign, accompanied by her husband Prince Philip, touched down at Casement Aerodrome, southwest of Dublin, at 11:55am (1055 GMT) to start the historic four-day visit, which is taking place amid a huge security lockdown. Earlier troops defused a bomb near Dublin following threats by republican hardliners. The landmark four-day trip is aimed at normalising relations between the two neighbouring states. But a visit intended to underline the progress made following the hard-won peace in British-ruled Northern Ireland also highlighted how dissident republicans still pose a threat. Irish police said a "viable explosive device" was found on a bus overnight in Maynooth, near Dublin, adding that they had been tipped off by an anonymous scare. The device was defused by the army, police and the military said. It came a day after dissident paramilitaries made a coded bomb threat in central London on Monday, the first of its kind outside Northern Ireland for 10 years. Police sealed off roads near the sovereign's Buckingham Palace residence and carried out a controlled explosion. Opposition to the queen's visit persists among a violent hardcore of republicans, who want British-ruled Northern Ireland to become part of the Republic, and a Catholic policeman was murdered in April. They remain a small minority, with the major republican groups having joined the political mainstream, and officials are doing their best to ensure the 85-year-old queen and her husband Prince Philip get a warm welcome. A 10,000-strong force is being deployed at an estimated cost of 30 million euros ($42 million), with reports saying the navy will be deployed off the Dublin coast to prevent a possible missile strike from the sea.