At least 21 people have been killed in Gaza in widening hostilities that officials say could bring down the two-month-old Palestinian unity government formed between Hamas and Fatah.
A group of journalists, were among hundreds of Gazans trapped in their offices or homes by the gunfire raging around them.
Hamas and Fatah declared a ceasefire at 8pm (17:00 GMT) - the fourth in as many days - but five fighters died in various clashes afterwards and gunfire and explosions could still be heard throughout the area.
Two Israeli air strikes in response to rocket attacks added to the chaos.
Three unidentified attackers fired on guards at the home of Ismail Haniya, the prime minister from Hamas, but no one was injured.
The violence has led to speculation that Mahmoud Abbas, the president from Fatah, may declare a state of emergency.
Odeh described Wednesday's violence as "the worst yet".
Some Palestinians see the fighting - which has killed at least 40 Palestinians since Friday - leading to all-out civil war and the end of the Palestinian Authority.
'No red lines'
Witnesses said masked fighters battled in civilian areas using rocket propelled grenades and machine guns.
"There are no red lines. There is no consideration for the safety of anybody," said Odeh, who found herself trapped along with dozens of other journalists as their office building got caught in the crossfire.
Terrified residents huddled in dark homes after electricity to some downtown neighbourhoods was cut off by a fallen power line.
In one panicked call to a radio station, a woman appealed to Palestinian leaders to act, pleading: "Do not leave us to die here."
Early on Wednesday morning, Hamas fighters stormed the home of Abbas's top security chief, Rashid Abu Shbak, in Gaza City, killing five guards.
In Wednesday's deadliest single attack, five detained Hamas fighters and two Fatah escorts were killed when their vehicle, travelling to a detention centre, came under fire.
Security officials said the vehicle was attacked by Hamas fighters, but a spokesman for Hamas's Executive Force said they were "executed ... in cold blood" by Fatah.
Hamas said another of its members was "executed" by Fatah fighters at a checkpoint.
Fatah said at least nine of its members were killed in Wednesday's fighting, including four guards at Abu Shbak's home, a member of Abbas's Presidential Guard and two members of Preventive Security.
Fatah's forces are larger in number. But many analysts believe Hamas's Executive Force and armed wing are better equipped and organised.
Adding to the chaos, Israeli aircraft carried out two air strikes on Gaza on Wednesday, killing four Hamas fighters in Rafah and another in the north. Two Palestinians were also wounded, residents said.
The attack came after Hamas fighters earlier fired rockets at the Israeli town of Sderot, injuring three people.
Ehud Olmert, the Israeli prime minister ordered a "severe response" to the rocket fire, according to a statement from his office.
Israel said the air strikes, the deadliest since a November truce in Gaza was declared, was not connected to the factional fighting but targeted a command centre used by Hamas to plan attacks and a rocket crew that had just fired into the Jewish state.
The Executive Force, which has taken a lead in fighting with Fatah, denied the Rafah building was used to plan rocket attacks and said the air strikes proved Israel was taking sides.
Pro-Hamas media have already begun accusing Abbas of lining up with Israel.
Israel agreed to let 450 Fatah troops into Gaza from Egypt on Tuesday.
Shimon Peres, the Israeli vice-premier, told reporters during a visit to Estonia: "We will not intervene in the war itself but if Mr Abbas will request specific help, we will supply [it]."
Source: Al Jazeera and Agencies