Police handled 135 cases of attempted smuggling of stimulants into Japan last year, of which 115 involved airplane carry-on luggage, the National Police Agency said Thursday.
There were 49 cases of stimulant smuggling using international flights to Japan in 2008, jumping to 127 the following year.
In 2010, the police uncovered such cases for the first time at Toyama, Okayama and Hiroshima airports, the agency said.
Stimulant smuggling from the United Arab Emirates increased from one case in 2009 to 11 last year, while cases originating in Nigeria climbed from four to 10 and those from Benin rose from none to seven, it said.
Last year the police accused 11,999 people of involvement in stimulant drug cases, up 3.0 percent from 2009.