Amid the current diplomatic impasse between Ankara and Jerusalem, Turkish hackers hijacked some 350 Israeli websites on Sunday evening, launching a Domain Name System (DNS) attack on dozens of other websites as well.

Israeli IT analysts said Tuesday the DNS hijacking is likely to be, in fact, a "test-run" ahead of a major attack on Israeli domains.

Visitors to some of the sites were diverted to a page declaring it was “World Hackers Day."

At least seven high-profile websites outside Israel were also hijacked, including those of The Telegraph, Acer, National Geographic, UPS and Vodafone.

Hackers calling themselves the "TurkGuvenligi group" claimed they had done the cyber-attack. TurkGuvenligi translates as "Turkish security."

"The hack represents a 10%-15% spike compared to the average number of daily hacks of Israeli websites," Shai Blitzblau, head of Maglan-Computer Warfare and Network Intelligence Labs, explained.

The operation was very sophisticated and probably entailed a significant financial investment, Blitzblau added.

An inquiry into the hack attack discovered a clear link to "TurkGuvenligi," as well as several failed attempts to hack other websites. 

Israel's military and security establishment has invested significantly in cyber-warfare programs in recent years and is considered one of the most advanced cyber-warfare forces in the world, both in attack and defense modes.

The Stuxnet virus that downed systems at Iran's Bushehr nuclear reactor to a halt for over six months is widely believed to have been the result of an Israeli cyber-attack, although Israel has not admitted it.