Led by Vietnamese monk Pannakara, the group of 13 launched their march at dawn from a historic Buddhist temple in Dambulla, about 160 kilometres (100 miles) north of the capital Colombo.

The monks shot to international fame during a longer 108-day walk of 3,700 kilometres (2,300 miles) from Texas to Washington, DC, travelling through freezing temperatures and along ice-covered roads.

In sharp contrast, they are now walking barefoot on Sri Lanka's roads at the hottest time of the year, when temperatures can reach 40 degrees Celsius (104 degrees Fahrenheit).

Devotees poured water on the streets, while some laid green banana leaves and flowers for the monks to walk on to escape the scorching heat. Others were seen sprinkling water to cool them.

The group, promoting "peace for all beings, including animals", was expected to reach the capital on April 28, where they will be received by President Anura Kumara Dissanayake, organisers told AFP.

Guarded by elite army commandos, their mascot Aloka -- a stray dog rescued in India -- walked on a leash, drawing bows and clasped hands from devotees lining the route.

Aloka had accompanied the monks in their peace walk in the United States.

The dog followed the monks in India and remained with them even after being hit by a car.

Aloka later accompanied the monks on their US journey, drawing global attention and donations that helped fund its travels.

"The cost of flying Aloka to Colombo from Texas was ten times that of an ordinary passenger taking the same route," a Sri Lankan monk handling local arrangements said.

Two army commandos were seen walking on either side of Aloka at the head of the quick-paced procession.

Sri Lanka's police kennels department was mobilised to ensure that local street dogs did not attack Aloka, who was led on a leash held by an army commando.

The peace walk's Facebook page has more than three million followers. A live stream of their Sri Lanka walk drew over 51,000 views in the first five hours.