Militant sources in Gaza tell CNN that a shoulder-launched anti-aircraft missile was used to try to shoot down an Israeli helicopter flying east of Gaza last week.
It is significant because it is the first time a weapon of this type has been used against an Israeli aircraft, though the missile did not manage to hit its target. Hamas, which controls Gaza, has not commented on the incident.
The weapon is said to be a Strela SA-7 and was smuggled in from the Sinai desert but originally came from Libya, according to a source in Gaza.
Libya has been grappling with a huge number of unaccounted for weaponry since the revolution that toppled its dictator, Moammar Gadhafi, and left everything from mines and mortars to anti-aircraft missiles in the hands of its citizenry. No group has taken responsibility for firing the surface-to-air missile from Gaza.
So far the Israeli military has declined comment and has not publicly acknowledged the provocation.
Speaking on the condition of anonymity, a senior Israeli Army official told CNN there has been a significant change in the kind of weaponry being used by militant groups in Gaza since the Arab Spring. The weapons are more powerful and sophisticated than have been used in times past.
In the past week, there has been an increase in rocket attacks from Gaza into Israel and subsequent air strikes by Israel on targets in Gaza.