The concentric circles of violence have scuttled a 5-month-old truce between Israel and Gaza militants and brought Palestinian factions that nominally share power to the brink of civil war. More than 70 Palestinians have been killed in the spasm of bloodletting that broke out Sunday.
Hamas militiamen took the internal Palestinian strife to an ominous new level by widening the group of targets, seizing aides to two prominent Fatah officials.
The U.S. has made no secret about which faction it is supporting in the near-civil war. It's backing Fatah, contributing $59 million to equip and train the palace guard of Fatah leader and Palestinian President Mahmoud Abbas, reports CBS News national security correspondent David Martin.
"When there is a showdown, we want the right people to come out on top," says Robert Satloff, executive director of the Washington Institute for Near East Policy.
Hamas has fired more than 100 rockets across the border this week, reports CBS News correspondent Robert Berger.
Israeli missiles came screeching down on Gaza at least five times Friday in retaliation for Hamas rocket attacks that have sent southern Israel into a state of panic. At least 13 rockets fell throughout the day, injuring four people in the rocket-scarred town of Sderot.
One of the air strikes incinerated a minivan carrying Hamas militants and what the army described as "a large amount of weapons." Three fighters were killed and 12 people were wounded, Palestinian hospital officials said.
"We were sitting outside my grocery store when a huge explosion shook the area and a small minivan turned into a ball of fire," witness Jawad Dallou said.
People in a nearby mourning tent grieving for a victim of the Palestinian infighting were also wounded, he said.
Five Palestinians, including at least three Hamas militants, were killed and six wounded in an earlier strike east of Gaza City. The military said the target was a Hamas headquarters building.
Other air attacks throughout the day caused no fatalities.
In all, at least 20 Palestinians have died in Israeli air strikes that began on Tuesday.
Hamas said the Israeli military called the house of Ahmed Jaabari, head of Hamas' military wing, and warned his family the building would be hit, too.
People converged on the house to protect it, he said. Jaabari was not at home, and the military had no immediate comment.
In other developments:
Despite the intensified attacks, a senior Israeli army official said Israel had no immediate plans for a major ground offensive to halt rocket fire, because it is reluctant to unite warring Palestinian factions against a common enemy. He spoke on condition of anonymity because no final decision has been made.
Six days of fighting between Hamas and Fatah have claimed more than 50 lives and all but destroyed a 2-month-old power-sharing deal between the two groups. The fighting was touched off by Abbas' deployment of thousands of troops in Gaza City last week to try to restore law and order — a move Hamas took as a provocation because it wasn't consulted.
The two abductions in Gaza on Friday broadened the mayhem because it was the first time senior civilians with ties to Fatah were targeted.