South American nations on Sunday backed Ecuador's decision to grant asylum to WikiLeaks founder Julian Assange, urging dialogue to end the crisis pitting Quito against London.

Foreign ministers of the Union of South American Nations, meeting in Ecuador's biggest city Guayaquil, expressed "solidarity" with Quito and urged the parties "to pursue dialogue in search of a mutually acceptable solution," according to a joint statement.

The statement, read by UNASUR Secretary General Ali Rodriguez of Venezuela, also declared support for Ecuador over the "threat of violation of its diplomatic mission" and reiterated the "sovereign right of states to grant asylum."

Britain has angered Ecuador by suggesting it could invoke the Diplomatic and Consular Premises Act of 1987, which it says allows it to revoke the diplomatic immunity of an embassy on British soil and go in to arrest Assange.

The 41-year-old Assange is fighting to avoid extradition to Sweden, where he is wanted for questioning over alleged sex crimes. He took refuge in June at the London embassy after exhausting all legal appeals.

Assange claims the accusations against him in Sweden -- made by two female WikiLeaks volunteers -- are politically motivated and that he would eventually be extradited to the United States, which was enraged when his website published a vast cache of confidential government files.

With British police posted outside the Ecuadoran embassy, it is unclear whether Assange will be able to leave the building.

British Foreign Secretary William Hague said Thursday that his government was obliged under its own laws to extradite the Australian national to Sweden.

On Saturday, the ALBA grouping of leftist Latin American and Caribbean nations also came out to support Quito, warning "grave consequences" if Britain breaches the territorial integrity" of Ecuador's embassy. (AFP)