Singapore has stepped up security measures following a series of explosions that rocked the Indonesian capital Jakarta on Thursday, Channel NewsAsia reported.

Deputy Prime Minister Teo Chee Hean, who is also Coordinating Minister for National Security, said Singapore was watching the developments "with concern" and had stepped up security measures.

"As close neighbours and friends, we are saddened by the loss of lives and injuries. We also agree to enhance cooperation for the security of our two countries.

"All of us can also help by staying vigilant. Let us stand together, united against possible security threats," he was quoted as saying.

READ: Jakarta attacks: All you need to know

Teo said he had called his Indonesian counterpart, Coordinating Minister for Political, Legal and Security Affairs Luhut Pandajaitan, to convey his condolences to the families and loved ones of those who died in the bomb blasts.

Reports said that at least six people, among them policemen, were killed and several others injured in several blasts in the vicinity of the Sarinah Mall in Jakarta at 10.50am.