Shortly before Laura Bush spoke Tuesday at the Republican National Convention in Minnesota, several explosions were heard near the Excel Energy Center.

St. Paul police Commander Doug Holtz told VOA tear gas was fired to clear crowds of people blocking streets after they had been given several warnings to disperse. He said some attempted to climb over the security fence surrounding the convention site and that large groups were moving through the downtown area.

Woman is arrested during protest at Republican National Convention in St. Paul, Minn., 2 Sept 2008

Security officials in full riot gear blocked reporters inside the secured area around the convention center from leaving.

On Monday, several U.S. journalists were arrested while covering an anti-war march on the opening day of the convention.

Amy Goodman, the host of a national radio and television program known as "Democracy Now," was among them. Goodman says she was arrested while trying to question police about two producers, Sharif Abdel Kouddous and Nicole Salazar, who had also been taken into custody while covering the demonstrations. Goodman and the producers were eventually released.

Democracy Now says Goodman was charged with a minor crime. Democracy Now says felony riot charges are pending against the two producers. The Associated Press reports one of its photographers was arrested by police moving in on a group of protesters in downtown St. Paul.

Police have said more than 280 people were arrested during Monday's event. Officials say that although most of the estimated 8,000 to 10,000 people who took part in the march were peaceful, some demonstrators smashed windows and tried to block roads. Police say about 130 people may face felony charges.

Some information for this report was provided by AP.