Within hours of learning that Minnesota’s first suspected case of swine flu had been confirmed, officials closed Rocori Middle School and said it won’t reopen until Wednesday.

At a news conference in Cold Spring this morning, Gov. Tim Pawlenty and Minnesota health commissioner Sanne Magnan both emphasized that they expect that there will be more cases in the state, probably fairly soon.

“This is a situation that is cause for concern, but not panic,” Pawlenty said, adding that in most cases in the United States, the so-called swine flu – now called H1N1 by most officials, including the governor -- has been no stronger than typical, seasonal flu cases.

What makes all of this more unusual, however, is that health officials have no way of knowing yet whether the flu will move in terms of spreading or becoming more severe.

“What we don’t know,’’ said Magnan, “is if it’s going to die out on its own, spread more, or whether it will be like 1918, when a mild phase was followed by a more severe phase. It’s unpredictable. The virus changes.”

Magnan said 100 specimens, mostly from Stearns and Anoka counties, have been tested, and all were negative. Ten more specimens remain to be tested at this point, she said.

The testing procedure should become more streamlined in coming days, she said.

Currently, the Minnesota Department of Health screens specimens before sending highly suspect specimens to the Centers for Disease Control and Prevention in Atlanta. The Minnesota department will  have the tools needed for full testing soon, she said.

For medical privacy reasons, officials at the news conference Thursday would not say whether the person at the Middle School was a student, teacher or other employee. At one point, Pawlenty corrected a reporter who asked about the sick “student.’’

“That’s person,’’ Pawlenty said. “You said ‘student.’ That infers the person is a student.”

As officials spoke, officials from the Department of Health were conducting an investigation as to how the infected person may have contracted the swine flu. The health department officials work in concentric circles, according to Magnan, starting with the infected person and working out to all people and contacts that person has made.

The decision to close the school was based on CDC guidelines, according to Rocori superintendent Scott Staska. At this point, only the middle school will be closed.

Staska asked for the cooperation of the local population in taking calls from health department officials.

Some people, he implied, already have become suspicious of callers.

“They (some residents) are afraid of the U.S. media,” he said. “They’re afraid of somebody trying to trick them into answering questions.”

Health department officials will clearly identify themselves, he said.

Staska also asked that all reporters leave school grounds at the conclusion of the news conference so that the schools remaining open “can operate as normally as possible.’’