Sinn Fein leaders said yesterday they were entering the Stormont talks, due to open officially tomorrow, to "smash the Union" between Northern Ireland and Britain.
The party president, Mr Gerry Adams, and its chief negotiator, Mr Martin McGuinness, reaffirmed traditional republican principles, saying they were entering the three-strand talks to achieve a united Ireland.
The trenchant tone and content of yesterday's statements are viewed as seeking to reassure supporters that - in the face of claims by Mr David Trimble that Sinn Fein has implicitly acknowledged the reality of partition by entering talks - its main goals have not changed.
"I think David Trimble should be aware that we have not struggled for the last 27 years against the might of the British government and the British military forces to take one step towards consolidating partition of this island," Mr McGuinness told a rally in Coalisland, Co Tyrone.
"Sinn Fein is not going to the negotiating table to strengthen the Union. We are going to smash the Union," he said.
"A reformed six-county state is not possible. What Mo Mowlam has to face up to is the reality that the whole world accepts the partition of Ireland is a failure. There can be no internal settlement within the North," he added.
Negotiating with unionists was not Sinn Fein's primary concern. "The key player we have to negotiate with is the British government. We are bringing a message to them that it's time for British rule to end, that is Tony Blair's big job," said Mr McGuinness.
Mr Adams, in a statement, said the British government must "join the ranks of the persuaders in seeking to secure agreement between all sections of our people. It isn't enough for Labour ministers to think that they can get away with introducing minimal change in order to minimise unionist objections," he added.
"The aim of democratic Irish opinion must be to seek a change in British policy from one of upholding the Union to one of ending the Union," said Mr Adams.
Mr Adams warned earlier that the Loyalist Volunteer Force planned an attack on a republican family. He told republican activists that "there is real danger at this time", and they should "urgently and immediately take measures to increase their personal safety".
Ulster Unionist Party security spokesman Mr Ken Maginnis said Mr McGuinness's speech amounted to a "vain promise" to smash the Union. The IRA, he said, would return to violence when it failed in its goals through talks.