Kolkata: Sister Nirmala, Mother Teresa's successor as superior general of the Missionaries of Charity, died here on Tuesday following renal failure and heart complications, church and order officials said. She was 81.

"She was sick for quite some time. She passed away at 12.05 a.m. today (Tuesday) at the convent where she used to stay in Sealdah," said a source at the Catholic religious order's global headquarters Mother House.

"Sister Nirmala had cardiac complications for long. Lately, she developed an acute kidney problem. She was taken to hospital but brought back to the MoC home two days back," said Archbishop of Kolkata Thomas D'Souza.

President Pranab Mukherjee and Prime Minister Narendra Modi, who led the nation in paying tributes, recalled her lifelong service to the cause of the poor. Modi's Nepalese counterpart Sushil Koirala also condoled the death of Nirmala, whose parents hailed from the mountainous nation.

Sister Nirmala became the second head of the order after its founder Mother Teresa stepped down from the post in March 1997. The Nobel laureate, who died on September 5 the same year, was in 2003 beatified as Blessed Teresa of Calcutta.

During her 12-year stewardship of the Kolkata-headquartered order founded in 1950, Sister Nirmala visited a large number of countries, opening new houses and drawing more people to the Missionaries of Charity, which now has under its fold over 4,500 religious sisters and activities spread across 133 countries.

She held the post till March 24, 2009, when she was succeeded by Sister Mary Prema.

Sister Nirmala's body was kept on a pedestal at the St. John's Church though the day where MoC nuns sang and prayed to celebrate her life, as a large number of tearful people gathered for the last glimpse of the simple but inwardly strong nun. West Bengal Chief Minister Mamata Banerjee was among those who paid her last respects.

An order spokesperson said the body would be kept overnight at a morgue in Tangra area. "On Wednesday morning, it will be taken to Mother House for public viewing. After the funeral mass at 4 pm, the body would be carried to the St. John's Church for the final rituals before being laid to rest at the adjoining cemetery."

The order mourned the death of its former head.

"We are deeply saddened and salute her life of service and dedication," said Sister Prema.

Sister Prema said after Mother Teresa, her predecessor took the order forward and worked tirelessly serving the poor and the needy.

The president in a tweet expressed his "heartfelt condolences".

"Hers was an inspiring life dedicated to service of the poor," he said.

Modi, in a statement, said: "Sister Nirmala's life was devoted to service, caring for the poor and underprivileged. Saddened by her demise. May her soul rest in peace." He expressed his "deepest condolences to the Missionaries of Charity family".

"With the demise of Sister Nirmala, the world has lost a great humanist social worker. I express my heartfelt condolences," Koirala tweeted.

In a message, Congress president Sonia Gandhi described her as a worthy successor of Mother Teresa and said Sister Nirmala would be deeply missed by the millions whose lives she touched in the service of humanity.

Party vice president Rahul Gandhi tweeted: "Extremely saddened at the passing away of Sister Nirmala. She carried forward Mother Teresa's work with quiet dedication and dignity."

Banerjee also expressed sadness, saying : "Kolkata and the world will miss her."

Describing it as a personal loss, she said the state government will extend all help and cooperation for the last rites.

International Society for Krishna Consciousness (ISKCON) also extended its condolences.

"Her life of dedication and service especially to the poor is a great inspiration and it is to be pondered upon and to be followed," said ISKCON spokesperson Radharaman Das.

Born Nirmala Joshi in Ranchi to a Brahmin family from Nepal in 1934, Nirmala joined the order after converting to Christianity in 1958.

An MA in political science and a trained lawyer, Sister Nirmala started the MoC's contemplative branch in 1976 and headed it till her election as the order's superior general.

She was elected for a second term in 2003.

Sister Nirmala was re-elected for a third term on March 13, 2009, but the MoC held a second election days later after she wanted to be relieved of the responsibility owing to ill-health and also expressed a desire to return to the contemplative life she led before heading the order.

She was honoured with India's second highest civilian order Padma Vibhushan in 2009 for her services to the nation.

(IANS)