U.S. Attorney General Eric Holder has acknowledged that it will be difficult to meet the January 22, 2010 deadline to close the U.S. detention center for terrorism suspects at Guantanamo Bay, Cuba. <br/><br/>He made his comment days after the House of Representatives voted to block detainees at Guantanamo from being transferred to U.S. soil. The measure last Thursday passed by a vote of 258 to 163, drawing support from both Democrats and Republicans.<br/><br/>