Then-senator Jesse Helms, a Republican from North Carolina, is shown leaving a TV studio where he announced in August 2001 he would retire after his term ended in 2003. Helms has died at 86. (Grant Halverson/Associated Press)Former U.S. senator Jesse Helms, one of the country's most provocative politicians and a loud opponent of Canada's business dealings with Cuba, died Friday at age 86.

The staunchly conservative Helms was first elected to Congress as a Republican in 1972 and went on to serve three decades in the seat.

Jimmy Broughton, Helms' former chief of staff, said the former senator died of natural causes in Raleigh, N.C. The Jesse Helms research centre said he died at 1:15 a.m. Friday.

Senate Republican Leader Mitch McConnell of Kentucky said few senators could match Helms' reputation.

"Today we lost a Senator whose stature in Congress had few equals. Senator Jesse Helms was a leading voice and courageous champion for the many causes he believed in," McConnell said in a statement.

The North Carolina-born Helms was seen as an icon of Republican conservatism but battled with politicians of all stripes during his five consecutive terms in office. He was nicknamed "Senator No" for blocking nominations and legislation.

During his time as chairman of the powerful Senate foreign relations committee, he used his position to influence a number of decisions. He was known for his strong and vocal stance against communism and big government.

"Compromise, hell! … If freedom is right and tyranny is wrong, why should those who believe in freedom treat it as if it were a roll of bologna to be bartered a slice at a time?" Helms wrote in a 1959 editorial that foretold his political style.

Ed Feulner, president of the U.S.-based conservative Heritage Foundation, said Helms was "one of the most consequential figures of the 20th century."

"Along with Barry Goldwater and Ronald Reagan, he helped establish the conservative movement and became a powerful voice for free markets and free people," he said.

He co-sponsored the Helms-Burton Act in 1996 that punished foreign companies, including Canadian ones, that did business with Cuba. At the time, he compared Canada's dealings with Cuba's Fidel Castro to pre-war British appeasement of Adolf Hitler.

Helms was an unrelenting critic of the United Nations, driving budget cuts that prevented payment of debts to the international agency.

He also opposed arms control and foreign aid, once describing it as throwing money down foreign rat holes.

But in later years he was open to compromise and worked with Democrats on legislation to pay back debts to the UN.

Helms supported prayer in public schools and opposed busing of students for racial integration. He also led crusades against abortion — which he likened to the Holocaust — and homosexuality.

In 1993, when then-President Bill Clinton sought to confirm an openly homosexual assistant secretary at the Department of Housing and Urban Development, Helms registered his disgust.

"I'm not going to put a lesbian in a position like that," he said in a newspaper interview at the time. "If you want to call me a bigot, fine."

But he also softened his views on AIDS, advocating greater federal funding to fight the disease in Africa and elsewhere overseas.

Later in life, Helms was slowed down by a variety of illnesses, including a bone disorder, prostate cancer and heart problems.

Before entering politics, Helms worked as a journalist, congressional aide, banking executive and political commentator. He also served in the U.S. navy for several years.

With files from the Associated Press