The queen laid a wreath at Ireland's war memorial garden to honour the Irish who fought for Britain in WWI [Reuters]

Queen Elizabeth II of Britain has marked a new era in the history of Anglo-Irish relations by visiting Croke Park in Dublin, Ireland's capital, where British troops massacred 14 civilians at a football match 91 years ago.

Eamon Gilmore, the Irish foreign affairs minister, said a British monarch visiting the site of November 1920's "Bloody Sunday" was a "hugely symbolic" moment.

He told the AFP news agency that the visit to the 82,300-capacity venue on Wednesday was "part of the making of a statement about the past", but would also acknowledge the key role that Gaelic games play in Irish life.

The incident saw 14 people, including a 10-year-old, killed by British forces when they opened fire on a crowd of thousands of spectators at a Gaelic football game in response to the murder earlier in the day of 14 undercover British agents.

Following the visit to Croke Park, the queen made what will be her only major speech of her trip at Dublin Castle, the former seat of British power in Ireland.

The queen acknowledged past British-Irish difficulties, speaking of "heartache, turbulence and loss".

Near the castle, police clashed with demonstrators opposed to the visit.

Earlier on Wednesday, the queen laid a wreath at the Irish National War Memorial Garden, which pays tribute to the 49,400 Irish soldiers killed fighting for Britain in World War I.

Bomb scare

The British monarch is on her second day of a four-day visit to Ireland, the first such visit in a century.

While noting the vast improvement in Anglo-Irish ties since a 1998 peace deal in British-ruled Northern Ireland, the queen is expected to tackle the tensions have existed between the two nations.

On Tuesday she laid a wreath in honour of those who died fighting for Irish freedom from Britain, bowing her head in respect at the Garden of Remembrance.

But there were rowdy scenes outside where several hundred republican protesters, kept streets away, chanted and torched a British flag.

Her arrival also coincided with the 37th anniversary of bombings in Dublin and Monaghan, the single bloodiest day in a three-decade sectarian battle over Northern Ireland.

The 85-year-old monarch arrived in the country amid heightened security, as a bomb was discovered on a Dublin-bound bus and two hoaxes also found near the city.

Thousands of police and state troops are on alert during her visit.

Meanwhile three vehicles were destroyed overnight on Tuesday in Londonderry, Northern Ireland, in a wave of arson attacks.

Dissident republicans threw petrol bombs into the car of a former Catholic politician Liam Bradley, whose son joined the police force, a police spokesman said.