Dublin, Ireland (CNN) -- Queen Elizabeth II's expression of sympathy for those who suffered during the long, bloody conflict between Ireland and England does not go far enough, the head of the Irish republican Sinn Fein party said Thursday.
Her "acknowledgement that the relationship between Britain and Ireland has not been entirely benign is a gross understatement," Gerry Adams said in a statement.
The queen is on a historic four-day visit to the Republic of Ireland, the first by a British monarch since Irish independence from London 90 years ago.
Adams, a pivotal figure in Northern Irish history as long-time leader of Sinn Fein, the IRA's political arm, said earlier that the queen's visit was "premature."
But that is mild compared to incendiary language he has used in the past, according to a journalist formerly based in Ireland.
"When the queen's cousin Lord Mountbatten was killed by the IRA in 1979, (Adams) said it was an execution that was fully justified," Toby Harden said.
Wednesday night, Queen Elizabeth expressed regret for the suffering of people on both sides.
"We can never forget those who have died or been injured, and their families. To all those who have suffered as a consequence of our troubled past, I extend my sincere thoughts and deep sympathy," she said.
Adams said he thought her sympathy was "genuine."
But he said it was not enough, demanding that "the future policy of her government (be) about building an entirely new future based on genuine equality, and mutual respect."
The queen, who was applauded when she began her remarks Wednesday night in the Irish language, acknowledged the complex relationship between the neighbors separated by water and different cultures.
On Tuesday she laid a wreath at the Dublin's Garden of Remembrance, which honors those who fought for Irish freedom from British rule.
During a trip laced with historically significant gestures, the queen has visited the National War Memorial Gardens in Islandbridge and Croke Park Stadium, where British troops opened fire on a crowd watching a Gaelic football match in November 1920, killing 14. The massacre was sparked by the murder of 14 British intelligence officers by the Irish Republican Army.
The visit has prompted police to mount a major security operation amid threats of dissident republican violence. Ireland has spent an estimated $42 million on security for the visit, according to officials.
Scuffles between protesters and police broke out Tuesday afternoon in central Dublin and the Irish military defused a bomb on a bus headed to Dublin. The military had stopped a private bus in Maynooth, evacuated the passengers and found a "viable device" in the luggage compartment, a spokesman for the Irish national police said.
The Irish War of Independence led to the partition of Ireland in 1921. The majority of the island gained independence, but six of the nine counties of the province of Ulster chose to stay in the United Kingdom, eventually becoming Northern Ireland.
In the late 1960s, the conflict between mainly Protestant unionists who want Northern Ireland to remain part of the UK and largely Roman Catholic nationalists who want the North to be reunited with the rest of Ireland exploded into a political and sectarian war, known as the Troubles.
The ensuing three decades of violence between the Irish Republican Army and loyalists claimed the lives of more than 3,000 people, most of them north of the border, and while the Good Friday Agreement, signed in 1998, effectively ended the conflict, suspicions remain.
CNN's Peter Wilkinson and Fionnuala Sweeney and Journalist Peter Taggart contributed to this report.