Palestinian police at the Gaza border with Egypt briefly detained a Hamas official this morning.
Sami Abu Zurhi was caught trying to smuggle almost €650,000 into the territory.
Hamas says it is unable to transfer cash to Palestinian territory to fund government activities and pay salaries, as banks fear US sanctions for dealing with the militant group.
The Hamas-led Palestinian Authority faces a severe financial crisis because of an international aid embargo.
Latest reports say the money has been released and put under the control of the Hamas-run interior ministry.
Earlier, at least three people were wounded in violence between rival Palestinian security forces in Gaza.
Clashes developed between police loyal to President Mahmoud Abbas and militias controlled by the Hamas-led government.
The US Secretary of State, Condoleezza Rice, said the situation was dangerous.
She said that having more than one security force just will not work.
The clashes sent terrified residents fleeing from the streets of Gaza City, where tension has soared amid fears of civil war.
Members of the Hamas force, mostly young militants, surrounded the main police station in Gaza City and traded fire with security men taking cover inside.
A spokesman for the interior ministry said fighting subsided after contacts between the forces.
Olmert to hold talks
Meanwhile, Israeli Prime Minister Ehud Olmert's top two deputies will hold talks with President Abbas on Sunday in the highest-level contact since Hamas swept to power in January.
The meeting, at the sidelines of the World Economic Forum in Egypt, will come on the eve of Mr Olmert's first trip to the United States, where he hopes to win President George W Bush's support for setting Israel's border in parts of the occupied West Bank.
The office of Foreign Minister Tzipi Livni said that she and Vice Premier Shimon Peres would hold a 30-minute meeting with Abbas and senior aide Saeb Erekat.
Mr Erekat, who announced the talks yesterday, said they would centre on reviving peace negotiations and freeing up Palestinian tax levies frozen by Israel after Hamas, an Islamist group sworn to destroying the Jewish state, won a January election.
