British Prime Minister Gordon Brown claimed progress Tuesday in defusing a simmering stand-off between Northern Ireland's leaders, after meeting them for a second straight day, his spokesman said. Brown, who travelled to Belfast on Monday for talks with First Minister Peter Robinson and his deputy Martin McGuinness, met the two men again at his Downing Street office in London. 'We must see it as a good sign that there is a follow-up meeting today,' said Brown's spokesman, while cautioning that the issues involved were 'complex.' 'There is a sense of momentum, and there has been significant progress,' he added. Robinson's Democratic Unionists (DUP) and McGuinness's Sinn Fein agree in principle on the transfer of policing and justice responsibility from London to Belfast, but disagree over the timing. Sinn Fein, the political wing of the defunct Irish Republican Army (IRA), says the powers should have been transferred months ago, but the DUP is demanding funding from London for the new justice department. The amount required is estimated at 600 million pounds (960 million dollars, 650 million euros). A 1998 peace accord ended most of the violence which had plagued Northern Ireland for three decades, killing at least 3,500 people. But fears of fresh violence were raised after two British soldiers and a policeman were shot dead in March, in attacks claimed by the Real IRA and another dissident republican group, the Continuity IRA. 