Complex sentence: The Greek authorities also warned the population of Korce that any action against incorporation to Albania would be fruitless and they assured that the Greek army will only hand over control of the region to regular Albanian units headed by Dutch officers of the International Commission.
Split into simpler sentences: The Greek authorities also warned the population of Korce that any action against incorporation to Albania would be fruitless. On the other hand they assured them that the Greek army will only hand over control to regular Albanian units headed by Dutch officers of the International Commission.