Somali pirate 'shoot-out' on ship
There has been a shoot-out between Somali pirates on a hijacked cargo ship loaded with 33 tanks, the East African Seafarers' Association says.
The maritime group's Andrew Mwangura told the BBC three men were shot in a row over tactics.
Pirates seized the Ukrainian ship last week and have demanded a $20m (£11m) ransom to release it.
Mr Mwangura said the situation is very tense with the ship, the Faina, surrounded by US navy vessels.
US navy spokesman Lt Nathan Christensen said on Monday that destroyers and cruisers has been deployed within 10 miles (16kms) of the hijacked ship.
We are asking the international community and the negotiators around that area to pull back - so they cool off
East African Seafarers' Association
Life in Somalia's pirate town
Meanwhile, Malaysian shipping company MISC Berhad says two of its oil tankers hijacked in August have been freed.
Company chairman Hassan Marican said ransoms were paid for MT Bunga Melati 2 and MT Bunga Melati 5, but declined to name the amount.
He said paying ransoms was against company policy, but necessary to obtain the release of its crew.
Somalia has been without a functioning central government for 17 years and has suffered continual civil strife, with rival armed clans and groups fighting for control.
Mr Mwangura said there are pirates from two different clans on board the Ukrainian-operated Faina.
Somalia's pirates face battles at sea
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"One clan is radical the other is moderate," he told the BBC's Network Africa programme.
It seems the radicals wanted to take hold of the shipment of 33 72-T tanks and other weapons, while the moderates wanted "to backpedal on the ransom issue", he said.
It was not immediately clear if the three men shot in the incident had survived.
Mr Mwangura said his main concern was the safety of the crew, and that the military activity in the area had unnerved the hijackers.
"We are asking the international community and the negotiators around that area to pull back - so they cool off."
One of the ship's 21 crew is reported to have died from an illness on board.
The Faina, which had been sailing to the Kenyan port of Mombasa, has been moored near the town of Hobyo.
Kenya has insisted that the shipment of tanks on board were destined for its military.
But other sources, including the US navy spokesman, have said they were bound for the autonomous government of South Sudan, in possible contravention of a UN arms embargo.
The waters off Somalia's coast are considered some of the world's most dangerous.
Even ships carrying food aid are often targeted, hampering the delivery of humanitarian supplies to the estimated three million Somalis in need of aid.
A Canadian navy frigate has been escorting food aid supplies for the UN World Food Programme over the last month.
WFP spokesman Peter Smerdon told the BBC Canada's mission is due to end on 23 October and no-one has offered to replace them.