In a briefing at the United Nations, the prime minister did not say when the Syrian ship was seized or the origin of the weapons. Iran has been Syria's leading military ally and supplier of weapons and equipment to quell the six-month revolt against Damascus.

"If in the future arms shipments are made by air or land, we will stop and seize them as we have done," Erdogan said.

Officials said Ankara, in coordination with the United States, has decided to sever relations with the Assad regime and bolster support to the Syrian opposition. They said the government has been hosting a growing opposition leadership in Turkey as well as bolstering its military relationship along the border with Syria.

Turkey has also been consulting with neighboring Iran over Syria and other regional issues. Erdogan said Ankara has sought to expand an Iranian intelligence exchange on the Kurdish threat in Iraq.

"We already cooperate in the field of intelligence to combat terrorism," Erdogan said. "We may undertake a joint effort over [Iraq's] Kandil."

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