World leaders on Monday mourned the death of Britain's first female prime minister Margaret Thatcher, reflecting on her influence both at home and abroad, and extending condolences to her family and people.

The "Iron Lady," who had suffered bouts of ill health in recent years, died peacefully on Monday morning at the age of 87 after being hit by a stroke, her family said.h Incumbent British Prime Minister David Cameron cut short his first ever official visit to Spain, canceling a press conference with his Spanish counterpart Mariano Rajoy and a visit to Paris to rush back to London.

"It was with great sadness that I learned of the death of Lady Thatcher. We have lost a great leader, a great prime minister and a great Briton," he said.

Rajoy also expressed his sorrow, saying she was an "authentic reference in 20th century history," adding she had governed Britain at a "key moment in history," showing her solid defense of her policies.

UN Secretary-General Ban Ki-moon, in a statement, recognized Thatcher's "pioneering stature" as the first female prime minister of her country, saying that she "will be remembered as a towering figure and as a strong and committed leader in British political life as well as on the international stage."

The UN chief also paid tribute to her contribution to addressing climate change, having been one of the first world leaders to issue a warning about its effects by calling for action at the UN General Assembly.

U.S. President Barack Obama mourned the demise of Thatcher, calling her "a true friend" of the United States.

"With the passing of Baroness Margaret Thatcher, the world has lost one of the great champions of freedom and liberty, and America has lost a true friend," he said in a statement.

"As a grocer's daughter who rose to become Britain's first female prime minister, she stands as an example to our daughters that there is no glass ceiling that can't be shattered," said Obama, who has two teenage daughters.

French President Francois Hollande extended his "deepest and very sincere condolences" to Thatcher's family and close friends, saying Thatcher's death "marks the disappearance of a great figure."

The French president said in a statement that Thatcher was "a great figure who made a deep impression on her country's history during her 11 years as British Prime Minister."

He said Thatcher had always maintained a "frank and loyal" relationship with France. "She forged a constructive, fruitful dialogue with Francois Mitterrand. Together, they committed themselves to strengthening ties between our two countries."

In a public condolence message, German Chancellor Angela Merkel praised the pivotal role Thatcher had played in overcoming Europe's Cold War division, saying her contributions to shaping modern Britain were unprecedented.

"Margaret Thatcher has demonstrated by herself what a female politician like her could claim in the highest rank of the democratic office, particularly in the days when women's participation in politics was still not taken for granted," Merkel said.

Canadian Prime Minister Stephen Harper said: "While many in positions of power are defined by the times in which they govern, Margaret Thatcher had that rarest of abilities to herself personify and define the age in which she served."

Brazilian President Dilma Rousseff also expressed her regret for the death of the former British leader.

Thatcher was Conservative prime minister from 1979 to 1990, the first woman to hold the post. She was a controversial figure, whose right-wing policies, including several privatizations, earned her both strong support and hatred.

Her role in the 1982 war against Argentina over the Malvinas Islands, known to the British as the Falklands, made her unpopular in South America.