UN chief Ban Ki-moon called Friday "on all governments" in the region to use to their influence to push against a new flotilla of ships expected to try to break the blockade on Gaza.
The secretary general was said to be "following with concern media reports of potential flotillas to Gaza," said his spokesman Martin Nesirky.
Some 1,500 activists are expected to take part in the convoy that will embark at the end of June, seeking to break the blockade of the Gaza Strip, a year after a deadly Israeli raid on a similar fleet.
Ban "called on all governments concerned to use their influence to discourage such flotilla, which carry the potential to escalate into violent conflict."
The UN chief also called on "all governments, including the government of Israel, to act responsibly and with caution to avoid any violent incident."
On May 31 last year, Israeli marines swarmed aboard the Mavi Marmara, the flagship of an international aid flotilla bound for Gaza, killing nine Turkish activists in international waters and plunging relations with Ankara into deep crisis.