Ecuador on Thursday waived preferential rights granted under a trade agreement with the United States, in a show of independence as it considers asylum for fugitive US intelligence leaker Edward Snowden.

"Ecuador unilaterally and irrevocably renounces these preferential customs tariff rights," Communications Minister Fernando Alvarado, said, reading from a government statement.

"Ecuador does not accept pressure or threats from anyone, and does not trade on principles or make them contingent on commercial interests, even if those interests are important.”

The government of leftist President Rafael Correa said that while it had received the preferential rights in exchange for its cooperation in the war on drugs, they had become a "new instrument of blackmail."

The 30-year-old Snowden, a former National Security Agency contractor who embarrassed the government of US President Barack Obama by revealing details of vast Internet and phone surveillance programs, has requested asylum from Ecuador.

Ecuadoran Foreign Minister Ricardo Patino has said it could take weeks to decide whether to grant asylum to Snowden, who remained Thursday in the transit area of a Moscow airport after fleeing Hong Kong.

(AFP)