ST. PAUL -- The Republican National Convention has suspended all but the most necessary activities to constitute a convention Monday and then will adjourn until further notice, John McCain, the presumptive Republican presidential nominee, announced Sunday.

No evening session will be called and no speakers will offer speeches on Monday night. President Bush and Vice President Cheney had both canceled their Monday night appearances at the convention earlier in the day.

The convention "will suspend all activities except those that are absolutely necessary," McCain said late Sunday afternoon. "We hope to resume some normal activities but frankly that is the hands of God."

McCain Campaign Manager Rick Davis said that additional activities will be determined on a day-by-day basis. He added that all activities at the convention will be procedural and not political.

Right now we have a horrible storm bearing down on the gulf. People should be more concerned about that than an political campaign, and I think that's the way we're going to let the chips fall," Davis said.

Davis said the only critical activities of the convention are its constitution through the gaveling in of the opening session, certification of the Republican National Committee delegates and the nomination of both McCain for president and Alaska Gov. Sarah Palin as vice president. The first two can occur on the Monday afternoon session.  The nominations had been scheduled for Wednesday.

In order to hold the convention, a quorum -- or 50 percent plus one of the delegates -- needs to be present. Davis said the quorum will be called at 3 p.m. ET Monday and the opening session will last a couple hours.

Davis said he encouraged the speakers to attend and deliver their speeches, but he did not want to speculate on whether McCain would attend. He called speculation the Arizona senator might not attend to accept his nomination as "completely immature" and "outside the scope of what I can tell you with any specificity."

"If conditions allow, we'd love to have him here, and that would be our preference, but again we're not making any commitments past 5:30 tomorrow afternoon," Davis said.

McCain said Sunday dramatic changes were to be made as convention organizers and meteorologists tracked Gustav, a Category 3 hurricane that is churning towards the Gulf Coast with potentially deadly force.

Earlier in the day, McCain was in Mississippi with his wife, Cindy, and running mate, Alaska Gov. Sarah Palin, to tour the emergency management center in Pearl, Miss., which could be the hardest hit area in the storm's path.

"We must redirect our efforts from the really celebratory event of the nomination of president and vice president of our party to acting as all Americans," McCain told reporters before the conventions events were suspended. He and Palin received a closed-door briefing by officials with the Mississippi Emergency Management Agency.

Cindy McCain and Palin were headed to St. Paul for Monday's opening session. Palin told a crowd of 15,000 supporters in O'Fallon, Mo., that victims of natural disasters need to know government is working for them.

"Some terrible days may lay ahead again for New Orleans again and for the region but, my fellow Americans, we will get through this crisis as we always do in our finest moments, by pulling together and by helping where the need is greatest. And moments like this, they turn the focus of our political debates back to fundamentals. They are a reminder, though, sometimes a very harsh reminder, that there are consequences when government fails to make good on its most basic obligations," Palin said.

McCain called on party members to "act as Americans" and "not as Republicans" because "America needs us now."

GOP sources familiar with the deliberations said they were considering asking the corporations to turn their gatherings into fundraisers for the Red Cross as a means of removing the celebratory nature from the parties. Those sources said the campaign would prefer no parties but many are already paid for and planned and the campaign can't tell people what to do.

"We will be communicating with all those corporations and individuals who will be holding various events and activities around the convention to please be respectful of the situation in the Gulf, and to employ them as a part of the extended fundraising network that we hope to establish in order to raise money for Gulf charities," Davis said, adding that the host committee planned to help with financial and material support to assist those relief groups.

McCain's campaign also chartered a DC-9 plane from St. Paul for any delegates from Louisiana and Mississippi who want to return home.

Bush had canceled his trip to St. Paul to go to Texas to monitor emergency response. Bush said he had been assured that New Orleans’ levees are “stronger than they have ever been,” but that there is a “serious risk of significant flooding” across the Gulf Coast, especially in that city.

“The message to the people of the Gulf Coast is this storm is dangerous,” he said. First Lady Laura Bush is still expected to attend.

Not everybody is prepared to abandon the GOP convention ship. While many lawmakers and others weren't going to be in attendance, some Louisiana delegates said they had a responsibility to be in St. Paul even as their homes were being battered by Gustav.

"The problems that we had before, I don't think we're going to have this time. The Army Corps of Engineers has done their job and I think we're going to see our finest hour here," said delegate Murray Nelson, adding that the delegates in attendance have safeguarded their families so that the delegates could uphold their legal responsibility.

"Every delegation has to cast their vote, and we wanted to make sure that we put our vote in and we get John McCain elected as our next president," Nelson said.

"We won't be able to get Gustav off our mind ... but we will try to pay attention to the convention, and we hope to cast our votes for John McCain," added Louisiana Delegate Finn French.

Texas Rep. Ron Paul, a former presidential candidate and representative of a district in the path of the storm, said he is not changing his plans because of the storm.

"I've been watching the cameras on the hurricanes as much as anything right now," Paul told FOX News. "I can understand people's concerns and wanting to express concern for what is happening but I am not sure how changing what we do here in Minneapolis will change anything in the Gulf Coast," he said.

"And it sort of makes the point when you talk in those terms that we sort of have control of the weather and it's everybody's responsibility, and I don't live on the coast. In fact, I had a beach house on the coast until about a year ago and I always thought it was my responsibility, you know, to get out of town. If my house gets blown away, I have to rebuild it. ... We're assuming that we have control of the weather and if there's a weather problem, everybody in the country has an absolute obligation to save everybody else," Paul continued.

FOX News' Mosheh Oinounou and The Associated Press contributed to this report.