Leaders of about four dozen nations and non-government organizations were called to Washington to discuss security of nuclear materials.
U.S. President Barack Obama convened the high-profile meeting to look into what he called the most severe security issue for the United States -- the possibility that a terror group such as al-Qaida obtained nuclear materials and used them in an attack on U.S. interests.
The environmental mess continued Wednesday as sewage treatment plants in Warwick and West Warwick remained inundated by the high waters and a major sewage pumping station in Cranston failed, The Providence (R.I.) Journal reported.
"The Pawtuxet River, from whatever sources, is being impacted by raw wastewater," said William Patenaude, an engineer at the state Department of Environmental Management who coordinates local sewer system programs. "This might be a historic first. This is obviously a situation beyond anything we're used to dealing with."
People in Warwick and other communities are being asked to conserve water by not taking showers, flushing toilets only when necessary and not running dishwashers or washing machines, the newspaper said.
"You had such a great number of businesses that were caught off guard; they didn't take steps to prevent this from happening," said Daniel Butler, vice president of retail operations for the National Retail Federation in Washington. "So it's going to be a longer recovery period."
USA Today reported the flood levels are unprecedented since Rhode Island began keeping records in the 1870s.
The attacks, said to be carried out by two female bombers, killed more than 20 people in a blast near the Russian intelligence agency and the others in an explosion not far away less than an hour later. Scores of people were injured in the blasts.
The Federal Security Service intelligence agency blamed a separatist Islamist group from the North Caucasus for the attacks. Last month a leader of the rebels in Chechnya warned their "military operations will be … coming to (Russian) cities."
Russian forces reported success in recent weeks in a crackdown on separatists in southern Russia. That came in the wake of a November bomb attack that killed 26 people on a train en route from Moscow to St. Petersburg. That bombing was blamed on Muslim militants from near Chechnya.
Russian President Dimitry Medvedev said: "The policy to suppress terrorism in our country and the fight with terrorism will be continued. We will continue the operation against terrorists without hesitation and until the end."