The Parliamentary Assembly of the Council of Europe (PACE) would be legitimizing the occupation of Crimea if it allows Russian delegates elected to Russia's lower house of parliament (Duma) to attend sessions after Russian parliamentary elections in September, Ukraine's permanent representative to the European Union Dmytro Kuleba has said.

"There is the risk if they [the Russian delegation] submit their credentials to PACE in January - and if they are not questioned – that the delegation would be allowed to return," Kuleba said during a press conference in Kyiv on Monday.

The diplomat said, "This would be a delegation from the new Russian Duma elected from occupied Crimea. In essence, PACE would be legitimizing the occupation of Crimea if it admits the Russian lawmakers."

Kuleba said Russia is attempting to return the assembly using key themes, such as the European refugee crisis and the Turkey issue following an attempted putsch in that country.

"The battle in PACE continues and depends on whether enough delegates in PACE can be convinced by pro-Russia advocates," Kuleba said.

He noted that if Russians see serious opposition sufficient to block the attempt, Russian delegates will not return to the assembly.