BRUSSELS - Belgium raised the alert status for its capital Brussels on Saturday to the highest level, warning the public to avoid crowds because of a 'serious and imminent' threat, a government official said. The threat level for the capital was raised to level four. The level for the whole country was raised to level three out of four, implying a possible or probable threat, following last week's Paris attacks. A spokesman for the government's crisis center declined to say why the alert status had changed.