Around 32,000 security personnel have been deployed across the Indonesian capital Jakarta after early "quick count" results confirmed Joko Widodo's victory in last month's elections.
Some schools have announced closures, while local offices have allowed staff to work, amid threats of protests by rival Prabowo Subianto's supporters.
The retired general, who was handed 44.5 per cent of the votes by the General Election Commission (KPU), "completely rejected" the results, and pledged to "continue to make legal efforts in line with the constitution to defend the mandate of the people".
Widodo, who won 55.5 per cent of the votes, said he will be a leader for all Indonesians.
"We are grateful and proud that amid our differences, we have been mature in keeping the peace," he said.
Qatar's prime minister said on Sunday that efforts to reach a new ceasefire in Gaza have made some progress but an agreement between Israel and Hamas to end the war remains elusive.
A huge blast most likely caused by the explosion of chemical materials killed at least 18 people and injured more than 700 on Saturday at Iran's biggest port, Bandar Abbas, Iranian state media reported.
The UN Refugee Agency (UNHCR) and the UN Office for the Coordination of Humanitarian Affairs (OCHA) have sounded the alarm over severe funding shortfalls that are hindering life-saving humanitarian aid in countries including Nigeria, Burundi, and Colombia.
A number of people were killed and multiple others were injured in Vancouver after a vehicle drove into a crowd at a Filipino street festival in the western Canadian city, police said on Saturday.