The president said he hoped that the new government, following a period of political and economic crisis, would  "inaugurate a new Palestinian era in which people live in peace and security".
 
Haniya has five weeks to put together the new cabinet and get it approved by parliament, which is dominated by Hamas.
 
Deadlock 
 
Your Views
Aid should not be restored until the conditions laid out are followed - its that easy
 
Last-minute demands by Hamas had raised doubts about whether the group would go ahead with the resignation.
 
Nour Odeh, Al Jazeera's correspondent in Gaza, said that disagreements remain between Hamas and Fatah over the position of interior minister and the future of Hamas's own 5,000 strong internal security force.
 
"There were a lot of sticking points that the Mecca agreement did not address."
 
Hamas and Fatah reached an agreement earlier this month in the Saudi capital Mecca after months of political deadlock.
 
The crisis spilled over into open conflict in which more than 100 people were killed.
 
International pressure
 
Abbas has asked the current government to continue until a unity administration can be formed.
 
Armed groups have clashed
on Gaza's streets [AFP]
The Palestinian president said: "I call upon you to respect Arab and international resolutions, and the agreements signed by the Palestine Liberation Organisation."
 
Hamas has never formally joined the PLO.
 
Haniya said he would "work in accordance" with Abbas's letter of designation.
 
It was unclear whether this went far enough towards meeting the demands of the quartet of Middle East negotiators (the US, EU, UN and Russia) that Hamas recognise Israel, accept past peace deals and renounce violence.

US boycott
 
However, the US has said it will continue to boycott all the new government's ministers, including non-Hamas members, unless international demands on policy towards Israel are met, a Palestinian official and diplomats said.

Tony Snow, a White House spokesman, said:  "Our conditions always remain the same."
 
"Those are the basic conditions and we certainly hope that Israel will find that partner we've worked with president Abbas and we continue to do what we can," he said.
 
The move would be a blow to Palestinian leaders, who hoped a unity government would lead to an end of a crippling Western aid freeze.
 
Condoleezza Rice, the US secretary of state, is to travel to the Middle East to hold joint talks with Abbas and Ehud Olmert, the Israeli prime minister, on Monday.
 

Source: Al Jazeera and agencies