Part of the OSCE international mission monitoring the Ukrainian presidential elections has left Eastern Ukraine, mission representative Thomas Rymer told Interfax.

Part of the observers is work ing in the places where voting is under way; half of the group left eastern regions, he said on Sunday.

He said that mainly long-term observers who have been monitoring the developments since April 2014 have remain ed.

He said that the regrouping of monitors were made due to security issues and also to the fact that many polling stations in Donetsk and Luhansk regions don't function and therefore there is no need for observers there, he said.

The international election monitoring mission comprises over 1,200 observers from 47 countries, including over 1,000 long-term and short-term observers of OSCE/ODIHR, 116 members and representatives of the OSCE Parliamentary Assembly, 46 observers from the Parliamentary Assembly of the Council of Europe (PACE), 18 from the NATO Parliamentary Assembly and 14 from the European parliament.

The OSCE mission will submit its report on Monday, May 26.