UPDATE 1-Economic crisis overshadows Bush farewell at U.N.

(Updates throughout with Bush speech)

By Jeremy Pelofsky

UNITED NATIONS, Sept 23 (Reuters) - U.S. President George W. Bush delivered his final speech to the United Nations on Tuesday addressing a world that has seen prolonged wars in Iraq and Afghanistan and a sweeping global financial crisis during his tenure.

Bush urged the annual General Assembly gathering of world leaders to fight terrorism and to enforce sanctions against Iran and North Korea over their nuclear programs.

He sought to address concerns about the financial market crisis, saying that he was confident a $700 billion rescue for Wall Street would be enacted in the "urgent time frame required."

U.N. Secretary-General Ban Ki-moon is worried that this and other bailouts will reduce the ability of rich countries to aid the developing world.

"Our economies are more closely connected than ever before and I know that many of you here are watching how the United States government will address the problems in our financial system," Bush said.

Bush's advisers in Washington are locked in negotiations with Congress over the administration's plan to buy hundreds of billions of dollars in illiquid assets from financial lenders' books.

But still high on Bush's agenda were the Iraq and Afghan wars and fighting terrorism.

"Instead of treating all forms of government as equally tolerable, we must actively challenge the conditions of tyranny and despair that allow terror and extremists to thrive," Bush said.

"Some suggest that these men would pose less of a threat if we'd only leave them alone. Yet, their leaders make clear that no concession could ever satisfy their ambitions."

SYRIA, IRAN

Nations like Syria and Iran continued to sponsor terrorism, but "their numbers are growing fewer, and they're growing more isolated from the world," Bush said.

He also urged the United Nations to enforce sanctions against Iran and North Korea over their nuclear programs.

Bush's senior aides will be working during the General Assembly for further sanctions against Iran, citing its refusal to cooperate with the International Atomic Energy Agency, which is probing allegations about Tehran's nuclear program.

Three rounds of sanctions and a package of economic incentives have failed to convince Iran to halt its nuclear enrichment activities.