PANAMA CITY - Military forces from 17 countries began on Monday the Panamax 2011 exercises aimed at preventing terrorist attacks against the Panama Canal and drug trafficking, the Panama Canal Authority (ACP) said.

ACP administrator Alberto Aleman Zubieta said 20 ships and airplanes along with around 3,500 personnel are taking part in the exercises scheduled to end August 26.

Aleman said Panama is responsible for the canal's security, but other countries' support, especially on intelligence, is also crucial.

The participating countries, all from the Americas, include Panama, the United States, Mexico, Argentina, Brazil and Canada.