"Israel cannot have stability with occupation. It has to choose. This is the message Israel should understand," he said in Abu Dhabi.
"Armed resistance is legitimate. All resistance options are open to the Palestinian people and Palestinian factions including Hamas."
Mishaal is touring Arab and Muslim countries to solicit financial and political support. He has said he informed Arab leaders that the government his group will head needs $1.75 billion a year and that he is confident that they will help.
Israel says it will not negotiate with a government led by Hamas.
Since its victory in Palestinian elections in January, Hamas has been under pressure from the US, the European Union and Israel to give up resistance and recognise Israel or lose financial aid to the Palestinian Authority.
"So long as there is an Israeli occupation in Palestine and so long as US policy is biased, the so-called terrorism that the United States fears will escalate because the mistakes of US foreign policy are pouring oil on fire," Mishaal said.
"It is illogical for the victim to be pressed to recognise its murderer and occupier"
He said his message to George Bush, the US president, was "that he should not worsen his mistakes".
Mishaal said Middle East peace required Washington to adopt an "even-handed policy that maintains the same distance from all sides" involved in the conflict.
He said Hamas would reject international pressure to recognise Israel until Israel was compelled to change its position on Palestinian rights.
"It is illogical for the victim to be pressed to recognise its murderer and occupier," Mishaal said. "What is required is a fundamental change in the Israeli position."
Mishaal said he had secured pledges for financial support during his tour, and that Arab countries would agree to reinforce allocations to Palestinians in a summit in Sudan next week.
"I believe that the Arab countries will agree in the Khartoum summit the level of aid they will offer the Palestinian people," he said.
"So far, there has been good commitment that needs to be translated into figures ...
"I am sure that Arab and Islamic support will cover a large part of the Palestinians' needs.
Palestinians protest over poverty
in Ram Allah in the West Bank
"No matter what Israel does and how much pressure the United States applies, I do not think Arabs and Muslims will cave."
Iran has said it will meet any gap in official funding for a new government once it is formed by Hamas in coming weeks.
But Mishaal said the Palestinian people could face a disaster if fellow Arabs did not also pay.
Israel has already cut off monthly payments of tax revenues it collects on behalf of the Palestinian Authority.
Mishaal said Hamas would not be bowed by the pressure.
"We are not isolated. We are a movement that enjoys the confidence of its people and has the capability to meet all its obligations," he said.
"We have succeeded in the past and we will succeed in the present and the future, God willing. Those who bet that we will lose are deluded."