An explosion occurred on a Greek tanker in the Saudi Arabia port of Al Shuqaiq, but no one was injured in the blast and the causes were still not clear, the Greek ministry of the merchant marine said on Wednesday. "The explosion happened around 0300 local time (0000 GMT), but the causes have not yet been identified," a ministry press official said. The Agrari MT tanker was flying a Maltese flag and there were 25 crew members onboard including seven Greeks, the official said. str-hec/pma/tgb