"We are planning to recruit another hundred which will bring us to 800," Zannier told reporters at the United Nations on Monday.
Zannier noted that the organization lacked access to some regions.
"We can throw more monitors on the line of contact. It’s extremely long. It’s 500 kilometers (310 miles). There are some areas where there are more intense combats. And because there are more intense combats we have to keep a little distance, I don’t want to risk lives of my monitors," Zannier added.
Kiev authorities launched a military operation against independence militias in eastern Ukraine in 2014. The confrontation has claimed over 9,000 lives, according to the UN estimates.
The OSCE has been tasked with monitoring the implementation of the Minsk deal provisions, which include a full ceasefire, a weapons withdrawal from the line of contact, an all-for-all prisoner exchange, constitutional reforms, including a decentralization of power in the country, and granting special status to the Donetsk and Luпansk regions.