Participants perform during National Day celebrations in Singapore on August 9./AFP
SINGAPORE - Singapore Tuesday celebrated its 51st anniversary as a republic with a heavily guarded parade after the discovery of an Indonesian extremist plot to attack the city-state.
The area around the National Stadium, where the military-civilian celebration took place, was designated a special zone where police had stop and search powers. The navy and coastguard conducted additional checks on vessels out at sea.
Air defences were also in place, local daily The Straits Times reported.
Singapore has been on heightened alert since Indonesian police arrested six suspected Islamic militants last week in nearby Batam island over an alleged plot to fire rockets into Singapore.
The wealthy Southeast Asian island nation, a strong military and economic partner of the United States, considers itself a prime target for terrorist attack.
The alleged leader of the Batam group is accused of planning the attack with a leading Indonesian militant who is now believed to be fighting with the Islamic State group in Syria.
Speaking in a pre-recorded National Day broadcast on Monday, Prime Minister Lee Hsien Loong repeated warnings of a potential attack on Singapore and called for national unity in case it happens.
"If a terrorist attack were to occur here, will we stand together, or will we fall apart?" he told his multiracial nation.
Tuesday's parade at the packed 55,000-seat stadium kicked off with a military drill before a festive show featuring some 5,000 marchers and performers from all walks of life, including 150 with special needs.
A display of military hardware, traditionally a key part of the parade, was removed this year because of the logistical challenges of holding it in the newly built stadium costing nearly $1 billion.
Following independence from Britain, Singapore became part of the newly formed nation of Malaysia in 1963. It broke away in 1965 to become an independent country.