Donald Rumsfeld, who served twice as U.S. defense secretary and was an important strategist in wars in Iraq and Afghanistan, has died aged 88.

Reaction to Rumsfeld's death was divided, Thursday - from honoring his decades of service to condemning the role he played in the Iraq War.

"Don Rumsfeld was a remarkable and committed public servant," former Secretary of State Condoleezza Rice said.

Arizona is deeply saddened by the loss of Donald Rumsfeld, a dedicated statesman and public servant who helped lead our country's defense following the 9/11 attacks," Arizona Gov. Doug Ducey said.

"Rumsfeld gave the orders that resulted in the abuse and torture of hundreds of prisoners in U.S. custody in Afghanistan, Iraq and Guantanamo Bay. This should be at the top of every obituary," Jameel Jaffer, Director at Knight First Amendment Institute at Columbia University, said.

"The country he helped break has still not recovered. This is his legacy. May he burn in hell for all eternity," according to İyad el-Baghdadi, president of the Kawaakibi Foundation, a research group concentrated on the Arab world.

President George W. Bush, under whom Rumsfeld served as defense chief for a second time, praised his ally.

"Don was in steady service as a wartime secretary of defense - a duty he carried out with strength, skill and honor...he was good-humored and big-hearted and he treasured his family above all else. Laura and I are very sorry to learn of Don's passing," Bush said in a statement.

His stint as Bush's defense secretary from 2001-2006 was his second, after serving as the youngest in the U.S. under former President Gerald Ford from 1975 to 1977, according to Al Jazeera.

Rumsfeld, who initially earned praise for leading the U.S. military into conflict, was later criticized as the country grew weary of the war, CNBC and other news organizations said.

Rumsfeld oversaw the U.S. invasion of Afghanistan in 2001 to remove the Taliban leaders who had harbored the al-Qaida leaders responsible for the Sept. 11 attacks.

He briefly ran for the Republican U.S. presidential nomination in 1988.

In the years following 60 years of public service, Rumsfeld served as chief executive of two Fortune 500 companies.

He died earlier this week from multiple myeloma, representative Keith Urbahn, said.

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