Lithuania is handing out an updated civil defence booklet to citizens telling them what to do in the case of a Russian invasion.

The 75-page manual offers survival techniques and warns readers Russia would not hesitate to use military force against its neighbours, the BBC reported.

A telephone hotline has even been set up for Lithuanians to report anyone they suspect are Russian spies.

The manual states: "It is most important that the civilians are aware and have a will to resist – when these elements are strong, an aggressor has difficulties in creating an environment for military invasion."

The country's head of state security, Darius Jauniskis, said: "Every Lithuanian citizen can become a target [of spying]."

Since the annexation of Crimea in 2014, relations between Russia and the Baltic states have deteriorated.

Lithuania borders on the Russian port of Kaliningrad which is cut off geographically from the rest of Russia.

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An American think tank has warned Nato that Russia could overrun the Baltic states in as little as 36 hours. Nato has been ramping up its presence in the Baltic states and Poland.

Lithuania is currently in talks to buy missile defence systems worth up to €100m (£90m) in an attempt to deter Russian aggression.