Former Pakistan prime minister Benazir Bhutto's killing should not be used as an excuse to put off elections in Pakistan indefinitely, United States presidential hopeful Barack Obama has said, stressing that the US' primary interest was to see a 'legitimate' government in the troubled country.

The Democratic senator from Illinois, who is seeking the party's nomination for the 2008 presidential elections, has said that it did not matter if the elections in Pakistan had to be postponed a little, adding that the bottom line was that the polls have to be legitimate.

"The key is to make sure that there's legitimacy to those elections. And given the enormous tragedy that has happened, I think that it is understandable if those elections are delayed slightly," Obama said.

"But it's important that this is not used as an excuse to put off, indefinitely, elections," he said.

He said the opposition parties should feel comfortable that they have the opportunity to participate in fair and free elections by reinstating an independent judiciary and making sure that there is a free press.

"Our primary interest is making sure that whatever government emerges in Pakistan is viewed as legitimate," he added.

"One of the things that we haven't focused on is that the vast majority of the Pakistani people are moderate and believe in rule of law. That's who we want as allies in the fight against Islamic extremism," Obama said.

Asked about his view on security arrangements for Bhutto, Obama stressed that Pakistan government should include opposition figures and people with credibility in a probe to ascertain what had happened.

"I think an investigation has to be completed to determine how the suicide bomber got as close to the former prime minister as he did, what exactly happened. That's why it's so important for us to ensure that we are providing all the assistance we can to the Pakistani government and that the Pakistani government is pressured to include opposition figures and, and people who are credible in the investigation process," Obama said.

"Until we know exactly what happened, I think it would be premature to judge that. What I do know, though, is that, moving forward, we have to have credible elections and we have to continue to pressure the Musharraf government, as I said back in August, to focus on the problem of Islamic extremism in Pakistan," he added.

Obama said Al Qaeda [Images] and the Taliban had taken root in the northwest province which was spilling over into the rest of Pakistan.

"This poses a grave danger. Benazir Bhutto [Images] herself recognised increasingly that this was one of the greatest threats to Pakistan and also to stability in the region and to the United States of America. And we have to ensure that whoever is in power is taking that process seriously," he said.