The Ukrainian border guard service has denied admittance to over 600 Russian citizens since the declaration of martial law, and the number of Russians wishing to visit Ukraine has fallen 66% over that period, Ukrainian State Border Service head Petro Tsyhykal has said.

"We have now denied admittance to over 600 Russian citizens. [...] The arrivals have dropped 66% over this period," Tsyhykal told the television channel UATV in an interview.

As to why female Russian citizens had been denied entry, he said there were a number of reasons, such as previous visits to Crimea, which Ukraine considers to have been annexed.

"A woman may be recruited and pose a threat. [...] There is such a notion as second-line control - we use a special questionnaire to conduct our interviews. If there is information regarding a woman or she cannot explain the purpose of her visit, we deny admittance. As a rule, only a handful [of female visitors] are rejected," Tsyhykal said.

In the past few days, Russia has denied admittance to Ukrainian citizens, even groups of 40 to 50 people, mostly men, without an explanation, he said.

On November 26, Ukrainian President Petro Poroshenko signed an executive order introducing martial law until 2 p.m. on December 26. The Verkhovna Rada endorsed the president's order on the same day. It was published in the parliamentary newspaper on November 28.

Martial law was declared in regions bordering Russia and Transdniestria (Vinnytsia, Luhansk, Mykolayiv, Sumy, Odesa, Kharkiv, Chernihiv, Kherson, Donetsk, and Zaporizhia) and the internal waters of the Sea of Azov and the Kerch Strait.