Fearing pneumonic plague spreading across the Sino-Russian border, Russia has tightened security on part of its border with China after an outbreak in Qinghai province.

But no signs of infection have so far been detected near the border, a spokesperson for the customs service in the Transbaikal area, to the east of Siberia's Lake Baikal, told Russia-based RIA Novosti news agency.

Qinghai is an inland province which is hundreds of km from the Russian border.