Former US President Jimmy Carter said in a statement: "Rosalynn and I are deeply saddened to learn of the death of Margaret Thatcher. A principled leader, she was a strong ally for peace and human rights during my presidency.
"As prime minister, her government was in the forefront of those who stood with the United States on key concerns, including the need for the SALT treaty, a stronger NATO alliance, majority rule in Zimbabwe-Rhodesia, and efforts to bring the Iran hostages home peacefully.
"We extend our condolences to her family and the people of Great Britain on their loss."
Former US President Jimmy Carter has paid tribute to Hugo Chavez, the Carter Center observed the 2000 elections in Venezuela.
Although we have not agreed with all of the methods followed by his government, we have never doubted Hugo Chávez's commitment to improving the lives of millions of his fellow countrymen.
President Chávez will be remembered for his bold assertion of autonomy and independence for Latin American governments and for his formidable communication skills and personal connection with supporters in his country and abroad to whom he gave hope and empowerment.
During his 14-year tenure, Chávez joined other leaders in Latin America and the Caribbean to create new forms of integration. Venezuelan poverty rates were cut in half, and millions received identification documents for the first time allowing them to participate more effectively in their country's economic and political life.
At the same time, we recognize the divisions created in the drive towards change in Venezuela and the need for national healing. We hope that as Venezuelans mourn the passing of President Chávez and recall his positive legacies - especially the gains made for the poor and vulnerable - the political leaders will move the country forward by building a new consensus that ensures equal opportunities for all Venezuelans to participate in every aspect of national life.