In November 2018 Russia fired upon and seized three Ukrainian Navy vessels (and imprisoned its 24 sailors in Moscow) off the coast of Crimea injuring crew members. The event prompted angry protests outside the Russian embassy in Ukraine and an embassy car was set on fire. Consequently, martial law was imposed for a 30-day period from 26 November in 10 Ukrainian border oblasts (regions). Martial law was introduced because Ukrainian President Petro Poroshenko claimed there was a threat of "full-scale war" with Russia. During the martial law (and starting on 30 November 2018) Ukraine banned all Russian men between 16 and 60 from entering the country for the period of the martial law with exceptions for humanitarian purposes. Ukraine claimed this was a security measure to prevent Russia from forming units of “private” armies on Ukrainian soil. On 27 December 2018 the National Security and Defense Council of Ukraine announced that it had extended "the restrictive measures of the State Border Guard Service regarding the entry of Russian men into Ukraine.”&lt;ref name="rubric-polytics/2609075"&gt;&lt;/ref&gt; (According to the State Border Guard Service of Ukraine) between 26 November and 26 December 2018 1,650 Russian citizens were refused entry into Ukraine. From 26 December 2018 until 11 January 2019 the State Border Guard Service of Ukraine denied 800 Russian citizens access to Ukraine.