JAKARTA, Sept 4 (Reuters) - Pope Francis on Wednesday urged political leaders in Indonesia, the world's most populous Muslim-majority country, to guard against religious extremism, which he said distorted people's religious beliefs through "deception and violence".

In his first speech during an ambitious 12-day journey across Southeast Asia, where Christians are a small minority of the regional population, the pontiff said the Catholic Church would increase its efforts toward inter-religious dialogue in hopes of helping tamp down extremism.

"In this way, prejudices can be eliminated, and a climate of mutual respect and trust can grow," the 87-year-old pope said in an address to some 300 politicians and religious leaders at Jakarta's Merdeka Presidential Palace.

"This is indispensable for meeting common challenges, including that of countering extremism and intolerance, which through the distortion of religion attempt to impose their views by using deception and violence," said Francis.

Indonesia has a population of about 280 million people and is estimated to be about 87% Muslim. Freedom of religion is guaranteed in the country's constitution.

There have been several incidents of extremist violence in the country in recent years, including suicide bomb attacks in 2021 and 2022 by persons affiliated with the Islamic State-inspired group Jamaah Ansharut Daulah (JAD).

The 2021 incident took place just before the Christian Easter holiday, and wounded at least 19 people.

In his own speech welcoming the pope to Indonesia, President Joko Widodo thanked Francis for his efforts to call for a ceasefire in the Israel-Gaza war.

"Indonesia appreciates the Vatican's attitude which continues to voice (and) call for peace in Palestine, and supports a two-state solution," said Widodo, who is stepping down in October after 10 years in office.

Francis was greeted by crowds waving small Vatican and Indonesian flags as his car arrived at the presidential palace.

Dorothea Dawai, a school child aged 10, was among the group welcoming the pope. Wearing a green kebaya, a traditional Indonesian dress, she said she hoped to ask for a blessing.

The pontiff, who suffers from knee and back pain, was seated in a wheelchair as he left his car, and met the president outside the building.

The two leaders were saluted by an honour guard playing the Indonesian and Vatican anthems, before heading inside for a private meeting.

Indonesian Foreign Minister Retno Marsudi told journalists that Francis and Widodo had not spoken specifically about the Israel-Gaza war in their meeting, but more generally about ongoing conflicts and "the importance of peace".

In his public remarks, Francis did not mention any specific violent incidents, but made several references to extremism, intolerance and manipulation of religion.

"There are times when faith in God is … sadly manipulated to foment divisions and increase hatred instead of furthering peace, communion, dialogue, respect, cooperation and fraternity," said the pontiff.

Francis' speech came on his first working day of the trip to Southeast Asia and the Pacific, which will also include stops in Papua New Guinea, East Timor and Singapore.

The pope is set to travel nearly 33,000 km (21,000 miles) on the 12 days of the tour, before he arrives back in Rome on Sept. 13.

Later on Wednesday, Francis is due to meet with Indonesia's Catholic bishops at Jakarta's cathedral. On Thursday, he will take part in an inter-religious meeting at the Istiqlal Mosque, the largest mosque in Southeast Asia.