Tensions over borders in the Andes continued, with the Ecuadorian–Peruvian War (1857–1860), a long-running conflict. Ecuador had effectively ceded long-disputed territory in the Amazon Basin to British creditors. This angered the Peruvian government, who demanded the transaction to be nullified. When Ecuador refused, war broke out. The Peruvian navy moved quickly to blockade the entire Ecuadorian coast and their army moved in and occupied Guayaquil, Ecuador's largest city and port. With little other option, Ecuador signed the Treaty of Mapasingue, declaring the cession null and settling the border dispute in Peru's favour. Ecuador regarded the treaty as inequitable, and the conflict was not to be resolved until late in the 20th century.