WARSAW, Aug 21 (Reuters) - A Maltese ship heading for Tripoli to pick up refugees came under fire and could not dock in the port, Polish foreign ministry officials were quoted as saying on Sunday by Polish state news agency PAP. "The ship is waiting for a better moment to enter the port because during its first attempt it came under fire," Paulina Kapuscinska, a spokeswoman from the ministry, told PAP. The ministry was not immediately available to confirm the report. Poland has evacuated most of its citizens from Libya and moved its ambassador from Tripoli to rebel-held Benghazi, but some 250 people from mixed Polish-Libyan families have stayed behind, the ministry official added. One family had hoped to leave on the Maltese ship, the MV Triva 1. Heavy fighting in Libya's capital broke out late on Saturday between rebels and remnants of Muammar Gaddafi's forces as the rebel forces try to capture the capital Tripoli. (Reporting by Patryk Wasilewski; editing by Elizabeth Piper)