Leaders mourn Margaret Thatcher

US President Barack Obama has said America had lost a "true friend" and the world a champion of freedom and liberty after Margaret Thatcher's death.

"As an unapologetic supporter of our transatlantic alliance, she knew that with strength and resolve we could win the Cold War and extend freedom's promise," Obama said in a written statement.

Kenya's President-elect Uhuru Kenyatta has sent a message of condolence to British Prime Minister David Cameron and British citizens following the death of Margaret Thatcher.

In his message, Mr Kenyatta said he is saddened by the death of the former Prime Minister, a formidable leader who radically transformed the country's economy.

"Lady Thatcher was a decisive and firm leader who will be remembered across the world for the role she played in pushing for free market economic ideology.

"To everyone who knew Lady Thatcher and had the opportunity to work and interact with her, the former Prime Minister was well respected as an iron lady of outstanding ability,” Mr Uhuru said in a statement sent to newsrooms on Monday.

Prime Minister Raila Odinga said she will be remembered not only as Britain's first female PM, but as a pioneer of many great ideas that transformed Kenya and many other nations worldwide.

He added that Mrs Thatcher had encouraged women’s involvement in politics and public life with famous quotes such as “if you want something said, ask a man; if you want something done, ask a woman.”

"She pioneered a closer scrutiny of what the role of the State should be in the lives of citizens, a debate that rages to date, and which led to improved conditions for many nations," he said in a statement.

Former President Daniel arap Moi also reiterated Mr Odinga's statement saying Mrs Thatcher was a great role model for women who want to join politics.

He said: “As the first British female Prime Minister and political party leader, Mrs Thatcher has inspired many women worldwide to venture into political leadership.”

The former President said he had worked closely with Mrs Thatcher to strengthen development cooperation between Kenya and Britain in the 1980s.

He recalled how she had boosted funds to build the ultra-modern Moi University library in Eldoret.

Other world leaders who sent their condolences are Canadian Prime Minister Stephen Harper, French President Francois Hollande, German Chancellor Angela Merkel, European Commission head Jose Manuel Barroso and former Soviet President Mikhail Gorbachev.