Iran's Foreign Minister Mohammad Javad Zarif on Thursday rejected as "lies" an Israeli claim that it intercepted a ship carrying advanced rockets sent by Tehran to the Gaza Strip.
"An Iranian ship carrying arms for Gaza. Captured just in time for annual (pro-Israel lobby) AIPAC anti Iran campaign. Amazing Coincidence! Or same failed lies," Zarif wrote on Twitter, referring to a pro-Israel lobby group.
Israel intercepted the "Klos-C" in the Red Sea on Wednesday, saying Syrian-made weapons aboard had been shipped overland to Iran and then onward by sea, intended for Palestinian militants in Gaza.
The annual policy conference of the powerful American Israel Public Affairs Committee (AIPAC) was held Tuesday in Washington, and was addressed by Israeli Prime Minister Benjamin Netanyahu.
In a meeting with the US President Barack Obama, Netanyahu said Iran was the most urgent threat for Israel.
"The claim of sending a ship carrying Iranian weapons to Gaza is not true," Deputy Foreign Minister Hossein Amir Abdollahian was quoted as saying by official IRNA news agency.
"This claim is merely based on the repetitive and unfounded lies of the Zionist media" aimed at derailing negotiations between world powers and Iran over its contested nuclear programme, he said.
In November, Tehran struck an interim deal with the six powers under which it agreed to scale back uranium enrichment in exchange for sanctions relief.
Obama threatened the congress in January to veto any new sanctions against Iran, since they would endanger the nuclear talks.
Iranian media said the allegation of the "imaginary ship" was a mutually hatched plot by the United States and Israel to put pressure on Tehran and its allies.
"It paves the way for intensifying pressure and Congress ratifying new sanctions against Iran as well as intensifying political and military measures against Syria," analyst Reza Seraj told Fars news agency.
"By linking Syria to Russia, they want to use the issue as leverage to gain political milage in Ukraine."
Iran has been a key regional supporter to Syrian President Bashar al-Assad as he has battled an armed uprising that erupted in March 2011.
Tehran is also a strategic allay of Russia which is at loggerheads with the West for sending its troops to Ukraine's flashpoint Crimea region.