After the 1689 Treaty of Nerchinsk, Russia lost the right to navigate the Amur River. Muravyov insisted on conducting an aggressive policy with China despite strong resistance from St. Petersburg officials, who feared a breakdown in relations between the two countries. Nevertheless, because the lower reaches of the Amur River were, in fact, being claimed by the Russians, several expeditions organized by Gennady Nevelskoy had been approved by the government. In 1851–1853, several expeditions were sent to the Amur Liman and Sakhalin, with Russian settlements being established in those areas.