Police intercepted a group of 70 Rohingya Muslims late on Saturday after they crossed the "zero line" border zone, where Myanmar soldiers earlier fired mortars and machine guns at villagers making the unsafe dash from the northern state of Rakhine into Bangladesh.
During Sunday prayers, the pontiff expressed solidarity with Myanmar's persecuted Rohingya Muslim community, calling for them to have "full rights".
Witnesses said they heard the sound of gunshots.
The treatment of about 1.1 million Muslim Rohingya in mainly Buddhist Myanmar has emerged as the biggest challenge for national leader Aung San Suu Kyi, who has condemned the attacks and commended the security forces. "In addition, the deportation of Rohingya Muslims back to Myanmar would also be a violation of Article 7 of the ICCPR in as much as it prohibits states to extradite, deport, expel or otherwise remove a person from their territory, where there are substantial grounds for believing that there is a real risk of irreparable harm".
Hundreds of Rohingyas are still stranded at the Naf river along the border with Bangladesh.
Despite measures to stop the influx, about 2,000 people have been able to cross into Bangladesh since Friday, according to estimates by Rohingya refugees living in the makeshift camps in Bangladesh, Reuters reported.
Roshida Khatun, 40, crossed into Bangladesh on Saturday morning along with more than 30 other Rohingya.
WFP sent a statement to the Guardian saying it took "any allegation of food diversions very seriously and we have requested more details from the authorities and asked to see the batch number of the biscuits as this will allow us to trace its origins and distribution site".
Bangladesh government sources say the unofficial policy is one of "closed doors, but open windows" - as there are many points along the more than 100km border which are easy to cross as they are not guarded.
The Rohingya are an ethnic minority who live mostly in Rakhine State - sometimes styled Arakan - on the western coast of Myanmar, and practice Islam.
The Rohingya, an ethnic minority in Myanmar, have long complained of religious and cultural discrimination at the hands of the majority Buddhist people.
The most recent flare up followed a report by a commission led by former UN Secretary General Kofi Annan on the conditions inside Rakhine.
But the journey was arduous - and many Rohingya did not make it, turned back at the border by Bangladeshi soldiers.
According to the Rohingya residents of the Balukhali camp, Bangladesh law enforcers have threatened them not to provide shelter to any newcomers or else they would be "evicted, fined and deported".
The note said, "Article 21 of the Constitution guarantees the "right to life" to all persons and not just Indian citizens".
Bangladeshi border guards are turning people away in an attempt to discourage refugees from seeking safe havens in Bangladesh, he said, but many people are waiting near the border before attempting another crossing.