"There are two ships in the Red Sea," he said, "What their intention is, what their destination is, I can't say."
Meanwhile, the US aircraft carrier USS Enterprise was transiting the Red Sea on Wednesday, after passing through the Suez Canal on its way to the US Navy's 5th Fleet area to support combat operations in Afghanistan and other duties in the region, two officials in Washington said.
Israel considers Iran an existential threat because of its nuclear program, missile development, support for militants and threats to destroy Israel.
While Israel has pressed for international sanctions to stop Iran's nuclear program, it has not taken the possibility of a military strike off the table.
Lieberman spoke to American Jewish leaders, but reporters were excluded. Later, his office released a statement with the charge about the Iranian ships crossing the Suez Canal on their way to Syria, a longtime ally.
"The international community must understand that Israel cannot ignore these provocations forever," he said, according to the statement. "We expect the international community to act with haste and determination against the Iranian provocations that are intended to destabilize the situation in the region."
Lieberman is known for his extreme pronouncements. Israel has been distributing dire predictions about the destabilization of the Middle East in the wake of the toppling of the regime of Egyptian President Hosni Mubarak, warning that Islamic militants could take over. Most experts play down that prospect.
The prices of benchmark Brent and WTI crude climbed after the report on the Iranian warships. Iran's action added to tension in the region and "absolutely moved markets," according to PFGBest oil analyst Phil Flynn. He said traders are worried that spreading unrest in the Middle East will disrupt oil production and shipments.
"The face of the Middle East is changing in pretty dramatic fashion in a very short period of time," he said. "The risk to supply is going up."