The Irish Republican Army admitted one of its units killed two Australian lawyers vacationing in Holland in what Dutch police said appears to have been a case of mistaken identity.

A massive manhunt by Interpol and British security forces has been mounted for two gunmen, who witnesses said were clad in black Monday when they shot Nick Spanos, 28, of Sydney, and Stephen Melrose, 24, of Brisbane, before speeding across the Belgian border in a car later found burned out in Belgium.Police have offered a $72,000 reward for information leading to their capture.

The two victims were on a holiday from London when they were shot about 11 p.m. Sunday in a crowded market square in Roermond, a Dutch town near the Belgian border and popular with off-duty British troops stationed in Holland.

The two gunmen apparently mistook the two lawyers for British soldiers, said Dutch police involved in the manhunt. Melrose's wife, Lyndal, and Spanos' girlfriend, Vicki Cross, also Australian, were unhurt in the attack.

The Irish government, in a statement issued Monday night, "unreservedly condemned" the killings.

Monday, the IRA issued a statement admitting the killings were the work of one of its active service units in Holland and claiming, "The shootings were a tragedy and a mistake."