Bomb Found in Ireland Hours Before Queen Arrives

The bus was traveling from Ballina in the west of Ireland toward Dublin and the device was found in Maynooth, 40 miles from Dublin. About 30 passengers had left the bus when it was stopped and searched, apparently after a tip by an informant, the police said.

News agencies reported that the Irish police also found a sham device, harmless but meant to appear to be a bomb, at a tram station in North Dublin. And a bomb threat that was received in London was regarded as credible by the police.

Despite the alarms, the queen and her husband, Prince Philip, flew into a military airfield outside Dublin, shrouded by one of the biggest security operations in recent years, both for the monarch and for President Obama, who is scheduled to visit the country early next week. The combined security effort is estimated to cost as much as $42.4 million, a large sum for a country in a deep economic slump.

The queen’s four-day visit, heavy with symbolism, is meant to finally signal reconciliation between Britain and a country that fought a bitter independence war against the British throne early in the 20th century. No reigning monarch had visited the island since the founding of the Irish Free State in 1922; the queen’s grandfather, King George V, was the last British monarch to visit, in 1911, when Ireland was still part of the United Kingdom.

The queen is to lay a wreath later Tuesday at a garden of remembrance, honoring those who fought against her forebears. She is also to visit the Croke Park stadium where British forces fired into a crowd during Ireland’s independence war and killed 14 people.

The Irish President, Mary McAleese, told the state broadcaster that the queen’s visit was “an extraordinary moment in Irish history,” while David Cameron, the British Prime Minister, said there was “a great sense of history and occasion” to the visit. But the symbolism was also offset by questions of security.

Planned routes for the queen to travel while in Dublin have been cleared for days of parked cars, and access to some areas has been blocked. More than 5,000 manholes, culverts and drains have been checked and sealed. Even the Dublin Zoo, which is close to where the queen will be staying, will be closed for two days.

Police north and south of the Irish border have arrested dissident republicans, detaining some of them, and surveillance is high. Citizens are being subjected to random searches around Dublin and elsewhere.

The measures reflect worries that dissident republicans who are opposed to both the Good Friday agreement in Northern Ireland and to the very presence of a British monarch on the island will mount some kind of attack. Weeks before the monarch’s visit, dissident republicans in Northern Ireland appeared armed and with their faces masked in a cemetery in Northern Ireland to warn Elizabeth that she was not welcome.

On Monday, the British police said that they had received a credible bomb threat in central London on the eve of the queen’s journey.

In a statement, a spokesman for Scotland Yard said on Monday that “a bomb threat warning has been received” but that it was “not specific in relation to location or time.”

Some areas of London were cordoned off, but no device was found, leading police to assume that the coded message was a hoax meant to complicate Elizabeth’s plans.

Central points around Trafalgar Square and Buckingham Palace were cordoned off as the police investigated the threat, and a suitcase left outside a hotel was destroyed by the police on Monday morning. Parts of the Mall were also shut down.

Police officials urged Londoners to be vigilant, but the threat designation for Irish-related terrorism had not been increased.

While the source of the threat remained unclear, suspicion immediately fell on dissident Irish republicans who have opposed the power-sharing government in Northern Ireland. The government includes the mainly Protestant unionists, who seek to keep the province a permanent part of Britain, and the mainly Catholic republicans, who want a united Ireland.

Opinion surveys suggest that many Irish people do not object to the monarch’s visit, but a minority remains opposed, accusing Britain of occupying Northern Ireland to thwart aspirations for a single Ireland.

Douglas Dalby contributed reporting from Dublin.