Four people, including a baby, were killed during weekend riots in Congo, the United Nations said on Sunday, in an early sign of unrest as authorities seek to discourage protests over delays to the first post-war polls. In the sprawling capital Kinshasa, heavily armed soldiers and riot police patrolled the streets on Sunday and a helicopter gunship buzzed overhead in a show of force to dissuade people from trying to undermine the transitional government, according to Reuters. Elections are the cornerstone of a 2003 deal to end Congo's five-year war and were due to take place by the end of June. They have been postponed until next year because of government wrangling, logistical delays and bloodshed in the east. Opposition politicians have blamed the delay on the government, led by President Joseph Kabila, and demanded it resign. They have called for peaceful protests next week to coincide with the original end of the government's mandate. "The soldiers have been sent into the streets and the choppers into the skies to make sure the message is clear -- we don't want trouble on June 30," a security source told Reuters. --More 2303 Local Time 2003 GMT