The Palestinian Hamas group has accused a key figure in the rival Fatah faction of trying to assassinate Prime Minister Ismail Haniya as he returned to
Hamas accused Mohammad Dahlan of orchestrating the attack as Mr Haniya crossed
Clashes have now broken out between Hamas and Fatah supporters in
A bodyguard died and Mr Haniya's son was among five hurt in the gun battle late on Thursday at the Rafah border.
Mr Dahlan has rejected Hamas's accusations of involvement, saying that Hamas, the governing party, was trying to "mask its failures".
'Grave threat'
Correspondents say the attack on Mr Haniya - and Hamas's open accusation of such a prominent opponent - have dramatically raised the stakes in the tense political struggle in the Palestinian territories.
Shooting erupted in
Hamas had deployed armed militants to key points in a show of force following the fire fight.
Hamas spokesman Ismail Radwan had earlier said the attack at Rafah was "an assassination attempt carried out by traitors led by Mohammad Dahlan".
Mr Dahlan is a former minister of internal security and a fierce critic of Hamas.
In the 1990s he led a crackdown on militants who refused to acknowledge the new Palestinian Authority (PA).
Fatah spokesman Tawfiq Abu Khoussa rejected Hamas's claims.
"Fatah has condemned the incident and is demanding the formation of an official investigation committee," he said.
"These accusations are posing a grave threat to Palestinian unity."
PA President Mahmoud Abbas, the head of Fatah, said he regretted the attack, but Hamas said he had to share some responsibility.
Mr Haniya, after his return to
Israeli Deputy Defence Minister Ephraim Sneh said his first response was to regret that the gunmen had missed Mr Haniya.
He told Israeli radio: "Emotionally, it was indeed my feeling. But upon coldly reconsidering it, I do not believe that that would have solved the problem."
Chaotic scenes
Inter-faction tensions have increased since the killing of three sons of a pro-Fatah security chief on Monday.
Mr Haniya had tried to cut short his first trip abroad as prime minister to deal with the crisis.
But Israel on Thursday closed the Gaza border, saying the reported $30m (£15.3m) Mr Haniya was carrying in donations as he returned from his foreign trip would fund "terrorist operations".
Mr Haniya crossed late in the evening following hours of intense negotiations, leaving the money on the Egyptian side. But at the border, guards allied to Fatah exchanged fire with Mr Haniya's security forces.
The BBC's Alan Johnston in
Television pictures showed Mr Haniya's jeep maneuvering to avoid bullets.
Hamas won elections in January, but has struggled in government amid a Western aid boycott against the militant Islamic group, which refuses to renounce violence and recognize
The Palestinian Authority has been unable to pay full salaries to its 165,000 workers.
Photo caption
Ismail Haniya back in