WASHINGTON - US Immigration and Customs Enforcement removed 368,644 illegal immigrants in fiscal 2013, down from 409,849 the previous year, the agency said on Thursday.

Acting ICE Director John Sandweg attributed the decline to two main factors: "... we did a better job of identifying serious criminal offenders; those cases take more time" and the changing composition of border removals, with more Central Americans which take longer than for individuals from Mexico.

The agency said in a report the overall figure for the year ended Sept 30 included 235,093 removals of individuals caught along the US border trying to illegally enter the country and 133,551 apprehended in the US interior.

Of those removed from the interior, 82 percent had previously been convicted of a crime, the agency said.

The majority of removals, 241,493, were individuals with Mexican citizenship, followed by 47,769 from Guatemala and 37,049 from Honduras, it said.