The Sept. 11 terror investigation reached to the Emerald Island Tuesday with the arrest of four men suspected of being linked to Al Qaeda.

Three Libyans and an Algerian, ages 24, 26, 31 and 39, were taken after police raids on five south Dublin properties, police spokeswoman Lynne Nolan said. The men were believed to have links to the terrorist network headed by Usama bin Laden, the suspected mastermind behind last month's devastating attacks. 

Police said they also seized suspicious documents and about $12,000 in cash during the raids

The arrests, by the force's Special Detective Unit responsible for Middle Eastern affairs, were the first in Ireland in connection with the U.S. attacks.

Three of the men were recent immigrants while the fourth was a naturalized Irish citizen who had lived here for two decades with his wife and children, police said.

The four were being questioned at two Dublin police stations under Ireland's anti-terror laws, which allow suspects to be held for up to 72 hours before being charged or released. Police rarely identify people in custody unless they are charged.

The Associated Press contributed to this report.