The European Union's drug agency says it identified a record number of new synthetic substances last year, most of them manufactured in China and India and then sold over the Internet.

The agency said in its annual report Thursday it detected 49 substances known as "legal highs" in 2011 - up from 41 in 2010 and a record for the third straight year.

The term "legal high" refers to substances that reproduce the effects of illegal drugs.

The Lisbon, Portugal-based agency said the number of online stores selling Europe's 10 most popular "legal highs" rose to 759 last year. That was just over double the number the previous year.

It said cocaine, ecstasy and amphetamines remain the most-used stimulants but face growing competition from synthetic alternatives.