KIEV (Reuters) - Ukraine’s border service said on Thursday it would only allow Ukrainian citizens to travel to Crimea following the imposition of martial law until Dec 26.

President Petro Poroshenko earlier accused Russia’s President Vladimir Putin of wanting to annex all of Ukraine and called for NATO to deploy warships to a sea shared by the two nations.

“In connection with the introduction of martial law, the administrative border with temporarily occupied Crimea can be crossed exclusively with Ukrainian documents,” a spokesman said.