From Moscow to Washington to New Delhi and points in between, dismay and condemnation poured forth Thursday over the assassination of Pakistani opposition leader Benazir Bhutto, along with concern for the stability of the volatile region. World leaders lauded her bravery and commitment to democratic reform.

In India, which has fought three wars against Pakistan, Prime Minister Manmohan Singh said Bhutto is irreplaceable, and noted she had striven to improve relations between the two nuclear-armed countries.

"I was deeply shocked and horrified to hear of the heinous assassination," Singh said. "In her death, the subcontinent has lost an outstanding leader who worked for democracy and reconciliation in her country."

Afghanistan's President Hamid Karzai, who met Bhutto earlier on Thursday in Islamabad, said he was "deeply pained" by the assassination of "this brave sister of ours, a brave daughter of the Muslim world"

"She sacrificed her life, for the sake of Pakistan and for the sake of this region," he said. "I found in her this morning a lot of love and desire for peace in Afghanistan, for prosperity in Afghanistan and ... Pakistan."

In a letter to Pakistani President Pervez Musharraf, French President Nicolas Sarkozy called the attack an "odious act" and said "terrorism and violence have no place in the democratic debate and the combat of ideas and programs."

Bhutto, a former two-time prime minister of Pakistan, was killed in a suicide attack in Rawalpindi just 10 weeks after she returned to her homeland from eight years in exile. A suicide attack on her homecoming parade killed more than 140 people. The articulate, poised 54-year-old had lashed out at the spread of Islamic extremism as she campaigned for next month's parliamentary elections.

The United States had been at the forefront of foreign powers trying to arrange reconciliation between Bhutto and Musharraf, who under heavy U.S. pressure resigned as army chief and earlier this month lifted a state of emergency, in the hope it would put Pakistan back on the road to democracy.

President Bush demanded that the killers be brought to justice.

"The United States strongly condemns this cowardly act by murderous extremists who are trying to undermine Pakistan's democracy," he said. He expressed his deepest condolences to Bhutto's family and to the families of others slain in the attack and to all the people of Pakistan.

U.N. Secretary General Ban Ki-moon also called for the perpetrators to be brought to justice and for "all Pakistanis to work together for peace and national unity."