Governor of Pakistan's Punjab province assassinated

(Reuters) - A gunman assassinated the governor of Pakistan's central Punjab province, a senior member of the ruling party, in Islamabad on Tuesday, an aide said, as a new political crisis gripped the strategic U.S. ally.

Salman Taseer was killed by one of his guards probably because of his opposition to Pakistan's controversial blasphemy law, Interior Minister Rehman Malik said.

Rights groups say the law is often exploited by religious extremists as well as ordinary Pakistanis to settle personal scores.

Islamist groups have been angry over what they believe were government plans to change or scrap the law.

The killing came as Pakistan's Prime Minister Yusuf Raza Gilani tried to muster support for the government after a key coalition partner quit.

A witness at the scene said Taseer was stepping out of his car at a shopping area when he was shot.

"The governor fell down and the man who fired at him threw down his gun and raised both hands," said the witness, Ali Imran.

The shooting left blood stains on a parking area on the edge of the Kohsar shopping center, which is popular among foreigners in Islamabad.

Pakistan's main opposition group said on Tuesday it would not force a no-confidence vote in the government, offering a reprieve but leaving the coalition weak after a main ally quit at the weekend.

The second-biggest opposition party also said it would not push for a no-confidence vote, suggesting the opposition may prefer to wear down a weak prime minister by blocking legislation or even through street protests to force a call for an early election.

The political turmoil adds to the difficulties of a government trying to push through economic reforms demanded by the International Monetary Fund, which has been propping up the economy with an $11 billion loan agreed in November of 2008.

(Reporting by Augustine Anthony; Writing by Michael Georgy; Editing by Robert Birsel)