Palestinian Prime Minister Ismail Haniyeh says financial pressure from an "unholy alliance" led by the United States will not bring down the new Hamas government.
Tens of thousands of Hamas supporters poured onto Gaza's streets to attend Hamas-sponsored rallies protesting aid cuts by the European Union and the United States.
Asserting that Palestinians were prepared to make sacrifices to keep Hamas in power, Haniyeh said: "We will eat cooking oil and olives."
Haniyeh said the consequences of bringing down the current government would be "grave".
He suggested that the Islamic militant group would be able to prevent any other government from forming to replace Hamas, which took power last month after winning parliamentary elections in January.
Hamas leader and lawmaker Younis al-Astal said the collapse of the current government could prompt the group to resume a suicide bombing campaign against Israel.
Washington and the European Union cut aid to the Hamas-led government because it has not renounced violence, recognised Israel or agreed to abide by interim peace deals.
The US Treasury Department also barred Americans, US companies and the US subsidiaries of foreign firms from pursuing most business dealings with the Palestinian Authority.
Analysts say that if the Hamas government collapsed because of lack of funds it would increase hardship and almost certainly provoke a dramatic rise in social and political instability.
Hamas says it inherited a Palestinian Authority with empty coffers and more than $1.3 billion in government debts.
Unable to pay March salaries to 140,000 government workers, Hamas and Palestinian President Mahmoud Abbas stepped up appeals to Arab states to make up for the loss of Western funds.
Without Arab aid, Hamas officials said the Palestinian economy could collapse within three or four months.
"The financial crisis is stifling. It has reached an unbearable limit," Abbas said at the end of a visit to Morocco.
In a rare appeal on its Web site, Hamas asked for donations at an account in Egypt's Misr International Bank, which French bank Societe Generale gained control of last year.
Societe Generale had no immediate comment.
A similar account set up at the Cairo branch of Amman-based Arab Bank, was closed, an Arab League official said.
Israel, which has frozen vital tax revenue transfers to the Palestinian Authority, said Hamas has only itself to blame.
"If it acts outside international norms, if it acts outside accepted International behaviour, then it can't be surprised if the international community starts to treat it like a pariah," said Mark Regev, Foreign Ministry spokesman.
But Haniyeh said the United States and Israel were mistaken if they thought the newly sworn-in government would fall in four to six weeks because of Western aid cuts.
"This government will continue for the full four years," Haniyeh told supporters at Jabalya, Gaza's biggest refugee camp.
Hamas has carried out nearly 60 suicide bombings against Israelis since a Palestinian uprising began in 2000, but has largely abided by a year-old ceasefire.
"Bringing down the government will mean the return for the policy of martyrdom operations and car bombs," al-Astal told 10,000 Hamas supporters in southern Gaza.
Haniyeh rapped Abbas, whose Fatah faction was defeated by Hamas, for issuing decrees making it harder for the government to rule.
"Hamas is not stupid," Haniyeh said. "I am not a weakling and nor are any of the ministers in my government."
Abbas, who has been struggling to keep peacemaking alive since Hamas's rise to power, rebuffed Haniyeh's criticism.
Abbas aide Nabil Abu Rdainah said the president had acted lawfully.
"The president renews his call on the government to deal with the current crisis with pragmatism," Abu Rdainah said.
Haniyeh said the United States had formed an "unholy alliance" that included pro-American Palestinians.
If his government were brought down, he warned, "What will happen? Will there be a new election? Will there be a government? We have a parliamentary bloc that holds the majority until the end of its mandate."
Like the United States, the European Union has severed political contacts with the Hamas-led Palestinian Authority.
In his speech, Haniyeh said some EU states had made contacts with the Hamas government, but he did not identify them.
