A vast haul of weapons seized by an Australian warship in the North Arabian Sea was bound for Somalia and may have originated in Iran, Defence suspects.
But neither their origin or final destination are known for sure.
Australian warships operating in the Middle East have seized large hauls of heroin from smuggling vessels in the past but the interception by HMAS Darwin in early March was the first involving a large quantity of weapons.
This haul comprised almost 2000 AK-47 assault rifles, 100 rocket propelled grenade launchers, 49 PKM light machine guns and 20 60mm mortar tubes.
HMAS Darwin was operating as part of a multinational taskforce engaged in counter-terrorism patrols.
French destroyer FS Provence, a taskforce member, also seized a large cache of weapons when it intercepted a smuggling dhow in the northern Indian Ocean earlier this week, including AK-47s, machine guns and anti-tank weapons.
The French military didn't release precise numbers but said they were believed headed for Somalia. Vice Admiral Johnston said this haul was also around 2000 weapons.
Both vessels were assessed to be stateless and, as they were bound for Somalia, the weapons were seized under the UN arms embargo.
Vice Admiral Johnston says the busts are unusual and could stem from improved intelligence.
A Defence spokesman says available evidence suggests the vessel intercepted by HMAS Darwin departed from Iran bound for Somalia, but the vice admiral says there's no firm evidence the vessel came from Iran.
Some US officials have suggested the weapons were bound for Yemen, where Iran has been supporting Shia Houthi rebels.
"We believe the weapons were bound for Somalia. Whether the US then formed the view that having entered Somalia, they may have been dispersed into Yemen, that's possibly their judgment," Vice Admiral Johnston told reporters in Canberra.
However, Somalia is also a point of entry for weapons bound for other parts of northern Africa.
The weapons seized by HMAS Darwin were transferred to another unnamed taskforce vessel to be disposed of, which could mean being thrown into the sea or possibly passed on to the allied forces.
