(Adds nationalities of monitors, diplomat quote)
VIENNA, May 27 (Reuters) - European security watchdog OSCE has lost contact with one of its teams of monitors near the city of Donetsk in eastern Ukraine, where pro-Russian militants are fighting Kiev government forces.
The team of four monitors - comprising an Estonian, a Swiss, a Turk and a Dane - came into contact with a road checkpoint on Monday at around 6 p.m. (1500 GMT) and had not re-established contact, a Kiev-based spokesman for the OSCE mission said on Tuesday.
The Vienna-based Organisation for Security and Cooperation in Europe (OSCE) said the monitors had been on a routine patrol east of Donetsk.
The OSCE said it had not yet been able to re-establish communication with the team of monitors. "We are continuing with our efforts and utilising our contacts on the ground. The Ukrainian government as well as regional authorities have been informed of the situation."
A Western envoy accredited to the OSCE said: "It is a very scary situation."
In early May, pro-Russian rebels in eastern Ukraine freed seven European military observers from a separate OSCE-linked mission after holding them hostage for eight days.
The 57-nation OSCE - which seeks to prevent conflict and promote democracy on the continent - decided unanimously in March to deploy civilian monitors across Ukraine to try to help to defuse the crisis there, so far without much success.
The mission consists of about 282 people, including 198 civilian international monitors from 41 OSCE countries, according to the Vienna-based organisation's website. (Reporting by Fredrik Dahl and Michael Shields in Vienna and by Gareth Jones in Kiev. Editing by Jane Merriman)