The United States has issued a postal stamp honouring Mother Teresa 'the diminutive Roman Catholic nun and honorary US citizen who served the sick and destitute of India for nearly 50 years.'

Designed by award-winning artist Thomas Blackshear II, the 44-cent stamp was released Sunday, the 13th anniversary of Mother Teresa's death, at a special ceremony held at the Basilica of the National Shrine of the Immaculate Conception in Washington, DC.

'Often, stamps are referred to as a nation's 'calling cards' because they reach a national, and even an international audience,' said Postmaster General John Potter in dedicating the stamp.

'They focus attention on subjects our country regards with respect and affection, and that is certainly true of Mother Teresa, who believed so deeply in the innate worth and dignity of humankind and worked tirelessly on behalf of the poor, sick, orphaned and dying.

'That's why today I am so very proud that our country, after making her an honorary citizen in 1996, is honoring Mother Teresa with such a lasting memorial.'

When Mother Teresa, who founded the Missionaries of Charity in 1950, accepted the 1979 Nobel Peace Prize, she did so 'in the name of the poor, the hungry, the sick and the lonely,' and convinced the organizers to donate to the needy the money normally used to fund the awards banquet.

Well respected worldwide, she successfully urged many of the world's business and political leaders to give their time and resources to help those in need.

US President Ronald Reagan presented Mother Teresa with the Presidential Medal of Freedom in 1985, the same year she began work on behalf of AIDS sufferers in the US and other countries.

In 1997, US Congress awarded Mother Teresa the Congressional Gold Medal for her 'outstanding and enduring contributions through humanitarian and charitable activities.'

Albania born Mother Teresa became a citizen of India in 1948. She died in Kolkata Sep 5, 1997. Her beatification was presided over by Pope John Paul II on October 19, 2003, in Saint Peter's Basilica, Rome. The cause of her canonisation continues and awaits the verification of a second miracle.