SINGAPORE - President Tony Tan Keng Yam and Prime Minister Lee Hsien Loong have written to Portuguese President Marcelo Rebelo de Sousa and Prime Minister António Costa respectively to express their condolences on the deadly forest fires in Portugal, the Ministry of Foreign Affairs said on Wednesday (June 21).

In his letter, Dr Tan extended his "heartfelt condolences and deepest sympathies" to his Portuguese counterpart and the Portuguese people on the loss of life and damage caused by the fires in central Portugal.

"Our thoughts and prayers are with those affected by this tragedy and their families. I wish them strength and resolve to overcome their difficulties through this period of adversity," he wrote.

PM Lee wrote in his letter to Mr Costa that he was saddened to learn of the devastating forest fires.

"On behalf of the Government of Singapore, I offer my deepest condolences to the bereaved families and those affected by the disaster," he wrote.

"Our thoughts are with the Portuguese people during this difficult time. We also pray for the safety of the rescue workers. I am confident that Portugal will overcome this disaster with fortitude," he added.

The massive forest fire swept through central Portugal at the weekend, killing 64 people, in the country's deadliest wildfire.

Many of the victims were burnt when they were trapped in their cars.

More than 100 people were also injured in the blaze that erupted on Saturday in the municipality of Pedrogao Grande.