Pope Francis arrives at the Uganda Martyrs' Shrine in Namugongo before celebrating Mass, Nov. 28, 2015. Carl De Souza/AFP/Getty Images

Pope Francis celebrated an open-air Mass at a shrine in Namugongo -- near Uganda’s capital city of Kampala -- on Saturday, to pay respects to Ugandan Christians who were burned alive at the site by a local ruler in the late 1800s. The visit is part of the second leg of his three-nation Africa tour.

More than 2 million people were reportedly expected to congregate at the shrine along with Ugandan President Yoweri Museveni to see the pontiff. Pilgrims camped out on mats and blankets from Friday, hoping to get a good spot to attend the Argentine pope’s first Mass in the country.

The somber-looking pope prayed at the Namugongo shrine dedicated to the 45 Anglican and catholic people, who were executed between 1885 and 1887 on orders of a local king eager to thwart the influence of Christianity in his kingdom.

On Friday, Francis hailed the extraordinary effort by Ugandans to accommodate refugees fleeing conflict and violence in the Democratic Republic of Congo and South Sudan.

The pontiff is also set to meet local religious leaders and hold a youth rally on his second day in Uganda.

While the pope drew global attention to the “achievements and struggles” of Africa and said that the "world looks to Africa as the continent of hope," Ugandan lawmakers passed a bill late Thursday that would give them sweeping powers to regulate non-governmental organizations.

Rights groups activists slammed the controversial bill and said it would "strangle" any criticism of the government. The bill reportedly gives Uganda's internal affairs minister and national board for NGOs powers to supervise, approve and dissolve an organization if "it is in the public interest to do so."

Human Rights Watch expressed concern that the broad and vague language of the bill would prompt fear and self-censorship among NGO workers.