Israel warned the United Nations on Thursday that two ships preparing to sail from Lebanon to the Gaza Strip to bring aid to the blockaded territory would not be allowed to reach their destination.
"The stated intention of these vessels is to violate the existing naval blockade of Gaza," Israel's U.N. Ambassador Gabriela Shalev said in a letter to Secretary-General Ban Ki-moon and Nigerian Ambassador Joy Ogwu, the current president of the Security Council.
Israel recently eased its blockade of the Gaza Strip in response to intense international criticism of a May 31 Israeli commando raid on a flotilla of aid ships. Nine pro-Palestinian Turkish protesters died in the confrontation.
Israel is allowing more food and other aid into Gaza via land crossings but continues to maintain the naval blockade.
Gaza has been controlled by the militant Palestinian group Hamas since 2007.
"Israel reserves its right under international law to use all necessary means to prevent these ships from violating the aforementioned naval blockade," Shalev said.
"Furthermore, it cannot be ruled out that these vessels carry weapons or individuals with provocative and confrontational intentions," she added.
U.N. officials have urged countries not to attempt to break the Israeli naval blockade and urged all parties to show restraint.
U.N under-secretary-general for political affairs Lynn Pascoe told the Security Council on Wednesday that "such convoys are not helpful to resolving the basic economic problems of Gaza and needlessly carry the potential for escalation."
Shalev noted that aid could be delivered to Gaza by land and said that those sending ships to the territory were doing so not to bring aid to the Palestinians but "to incite a confrontation and raise tension in our region."