Both chambers voted to let the US, Argentina, Brazil and Chile impose a final treaty.

All four are neutral guarantors of a 1942 treaty that set the border between Peru and Ecuador.

They have been helping peace talks between the two countries since a brief war in 1995 over a section of the frontier that was never clearly demarcated

Each parliament had been asked to approve a final peace settlement which has yet to be written.

Presidents failed to agree

Parliamentary approval was sought after talks between President Jamil Mahuad of Ecuador and Peru's President Alberto Fujimori stalled.

The BBC's South America correspondent James Reynolds says the two heads of state could not agree on the final demarcation of the disputed border, an 80km stretch of land in the Amazon jungle.

After the talks broke down both sides realised they could not resolve the dispute alone.