ST LOUIS - REPUBLICAN White House hopeful John McCain and running-mate Sarah Palin will ditch their pre-convention plans on Sunday and visit people in Mississippi bracing for deadly Hurricane Gustav.

The visit comes as the fearsome category four storm's approach overshadowed the buildup to the Republican National Convention in St. Paul, Minnesota on Monday, and stirred memories of the botched response to Hurricane Katrina exactly three years ago.

'Yes it's confirmed we are going to Mississippi in the morning' on Sunday, campaign spokeswoman Kimmie Lipscomb told AFP, after Mr McCain flew into midwestern Missouri for an overnight stop.

Both Mr McCain and Democratic nominee Barack Obama were carefully laying the groundwork to respond to Gustav's certain political fallout, as the storm loomed as test of their leadership skills.

Mr McCain asked supporters at a rally in Washington, Pennsylvania on Saturday to keep their thoughts and prayers for the people on the Gulf Coast, where the fearsome storm is expected to make landfall on Monday.

'They need to know ... that they're in our thoughts and prayers as this impending hurricane approaches.

'We pray to God that it will spare them and a minimum of loss that might result from this natural disaster.'

Earlier, in an interview to be broadcast on Fox News Sunday, Mr McCain suggested he might go as far as suspending the convention, if the storm turned into a huge human tragedy on the par with Katrina.

'It wouldn't be appropriate to have a festive occasion while a near tragedy or a terrible challenge is presented in the form of a national disaster.

'So we're monitoring it from day-to-day and I'm saying a few prayers,' he said.

Hurricane Gustav took aim at the United States early Sunday after leaving at least 81 people dead in the Dominican Republic, Haiti and Jamaica and causing damage in Cuba.

Forecasters said the storm could hit top category five force as it moved toward the US Gulf Coast for a direct hit Monday or Tuesday.

In any case, 'Gustav is forecast to remain a major hurricane through landfall along the northern Gulf coast,' the US National Hurricane Centre said.

Republican officials in St. Paul said there were no current plans to alter the convention program.

But party leaders are highly sensitive to the political implications of the storm. The Republican brand has yet to recover from President George W. Bush's botched response to Katrina, which obliterated parts of New Orleans and left a total of 1,800 people dead.

Mr Obama, campaigning on Saturday with his running mate Joseph Biden in Ohio, said that his campaign was 'deeply concerned' about the approaching storm.

'I've instructed my Senate staff to monitor the situation closely.

'You know, obviously we're going to be each day seeing what happens and we're praying for New Orleans but we want to make sure that people are making all the necessary precautions.'

White House spokesman Carton Carroll said Mr Bush had not so far changed his plans to address the convention on Monday.

'It is true that we are monitoring the situation, of course, and there is a chance we can change the schedule, but at this time we have not made any changes,' he said.

The Republican convention will crown Mr McCain as its official presidential candidate in the Nov 4 elections, to take on Mr Obama who made history last week when he was nominated at the party's Denver convention as the first black presidential candidate for a major party. -- AFP