The Israel Defense Forces (IDF) has started calling up 16,000 reservists for ongoing military operations against Palestinian militants in the Gaza Strip, an IDF spokesperson said Friday.

The reinforcements are part of the 30,000 reservists called up by Israeli Defense Minister Ehud Barak for a possible ground incursion in Gaza.

The order came shortly after two rockets were fired at the greater Tel Aviv area. The attack was the first against Israel's largest city since the 1991 Gulf War. The IDF intensified its aerial and maritime strikes on targets in the coastal territory following the attack.

The IDF said in a statement that during overnight attacks the IDF targeted approximately 150 medium-range rocket launching sites as well as ammunition storage facilities across the Gaza Strip.

"As a result of the continuous IDF targeting rocket launching capabilities, rocket fire at Israel overnight was significantly decreased, with only a few hits landing in open areas," the statement said.

Since the start of Israel's Operation Pillar of Defense against Hamas on Wednesday, the Israeli Air Force has targeted over 450 sites in the Gaza Strip.