Jakarta - Indonesian President Joko Widodo has called for calm after attacks in the capital Jakarta killed at least seven people."We must not be afraid and be defeated by this terror act," Joko was quoted as saying by Kompas.com news website. "I appeal to the people to remain calm," he said. At least seven people, including four suspected attackers, were killed in a series of bomb and gun attacks on Thursday, police said. Three police officers were seriously injured in the attacks near the Sarinah shopping complex in central Jakarta, city police spokesman Muhammad Iqbal said. "Four suspected perpetrators were killed in a gunfight with the police," Iqbal told TVOne. He said police believe no attackers are on the loose.Police exchanged fire with suspected attackers after the blasts at a traffic police post in front of the Sarinah shopping centre and a nearby Starbucks coffee shop, said Ruly Koestaman, an office worker in a nearby building in the busy city centre."I was in a meeting when I heard an explosion and then there was gunfire," Koestaman said. "We went down and saw three people lying dead, and also two foreigners badly injured but still alive," he said. A mobile phone video taken from a high-rise building showed one of the explosions followed by smoke billowing from the location.