Hindus in Malaysia have marked the festival of Thaipusam, one of the most important in their religious calendar, displaying their devotion in a mass procession with some piercing their bodies with hooks and skewers.

Authorities said they were expecting as many as two million people – devotees and tourists – at the Batu Caves temple on the outskirts of the capital, Kuala Lumpur, on Thursday. A further one million people were expected to take part in the festival on the northern island of Penang.

Thaipusam commemorates the day when Goddess Parvati gave her son Lord Murugan a “divine spear” to vanquish an evil demon who had taken control of heaven and taken its heavenly beings captive.

The festival represents the struggle between good and evil, and is celebrated not only in Malaysia but also in Singapore, India, Sri Lanka and other countries with large numbers of Tamil people.

Devotees at Batu Caves climb 272 steps to reach the top of the temple hidden within a limestone cave.

“I think because you’re constantly praying, you don’t really feel it,” Jaynita, who asked to be identified only by her first name, told the AFP news agency.

“Once you go in you are in a mode of like, Zen, you just think about the God [Lord Murugan] and you just want to reach him,” she added.

The 30-year-old and her sister carried milk pots on their heads as offerings to God to thank for the improved health of family members who had been in poor health.

“When they get better, we believe that it’s because of him. So we fulfil the vow since he fulfilled what we asked for,” she said.

Some devotees carry heavy metal structures known as kavadis, which can weigh as much as 100kg (220 pounds) and are attached to their bodies with sharp metal spikes.

Others pierce their tongues and cheeks with metal skewers as a show of thanksgiving and penance.

Many participants go into a trance known as “arul vaku”, which means they do not feel pain or bleed from the piercings.

In the weeks running up to Thaipusam, devotees typically hold daily prayer sessions, abstain from sex and maintain a strict vegetarian diet to “purify” their bodies.

Ethnic Indians, most of them Tamil, make up about 7 percent of Malaysia’s 34 million people.