An article I came across while browsing about Iran and its up coming news release about their nuclear program

BUCHAREST (Reuters) - Romanian oil firm Grup Servicii Petroliere (GSP) said on Tuesday one of its offshore drilling rigs in the Gulf came under attack by an Iranian military helicopter.
http://news.yahoo.com/s/nm/20060822/...n_romania_dc_1

Is this a legimate action by Iran to protect its terroritial waters and the oil underneath it, or is it piracy on the high seas by a national government?