Six people were killed and seven others were injured after landslides and flash floods hit Indonesia's North Sumatra province.According to the Operational Unit of the Provincial Search and Rescue Office, the natural disasters occurred in two regencies. The landslides struck Padang Lawas regency, resulting in four deaths and four injuries.Flash floods hit South Tapanuli regency, killing two people and injuring three others.Landslides occur frequently in Indonesia. Heavy rains in May caused floods and mudslides that killed more than 50 people in West Sumatra. A month earlier a landslide caused by heavy rains in South Sulawesi killed at least 18 people.