U.S. President Barack Obama said on Saturday legalizing growing or consuming drugs won't solve the problem of a brutal drug war south of his country's border.

(SOUNDBITE) (English) U.S. PRESIDENT BARACK OBAMA, SAYING:

"It is entirely legitimate to have a conversation about whether the laws in place are ones that are doing more harm than good in certain places. I personally, and my administration's position, is that legalization is not the answer."

With calls from around the world for a fresh look at how to stop a violent, multibillion dollar illegal trade, drugs are a focus for American leaders at the Summit of the Americas in Colombia.

Colombia's President Juan Manuel Santos said his country's crackdown on guerilla groups controlling vast swaths of land has made a difference...but the drug business knows no boundaries.

(SOUNDBITE) (Spanish) COLOMBIAN PRESIDENT JUAN MANUEL SANTOS:

"We can say that all the indicators show that we have been successful, however we know that our success has created problems in other countries, the famous 'balloon effect', the effect of a water bomb where you squeeze and water goes to the other side."

Some in South America believe decriminalizing the growing of coca - the raw ingredient for cocaine - would slash revenue for traffickers and encourage farmers to plant different crops.

Katharine Jackson, Reuters.