Pope Francis may not have been the first pontiff to tweet, but he is certainly the most active one yet. Since becoming head of the Catholic church in 2013, the bishop of Rome has continued to embrace social media as a way to reach more people, garnering over 10.4 million followers on Twitter alone.

However, supporters of President Donald Trump have criticised the pontiff for seemingly throwing shade at the US president on Twitter over his controversial policies including the refugee ban, the US-Mexico border wall and his stance on immigrants.

On 15 February, the pontiff's official Twitter account tweeted: "The throwaway culture is not of Jesus. The other is my brother, beyond every barrier of nationality, social extradition and religion."

"How often in the Bible the Lord asks us to welcome migrants and foreigners reminding us that we too are foreigners," Pope Francis tweeted from the official Twitter account on 18 February.

One Twitter user responded: "Even God believed extreme vetting was a good thing. Moses didn't get into the promised land." Another user wrote: "Go ahead and see Christianity destroyed like it has been in the Islamic lands."

On Wednesday, Pope Francis tweeted: "Jesus entrusted to Peter the keys to open the entrance to the kingdom of heaven, and not to close it."

Trump supporters quickly hit back at the pontiff with tweets of their own, arguing that even heaven has a gate and the Vatican has its own wall.

Earlier this month, Pope Francis also appeared to criticise President Trump's policies without directly referring to the US president in his comments.

In a statement at his weekly general audience at the Vatican, Pope Francis called on people to build bridges rather than walls, The Guardian reports.

Shortly after Trump's inauguration in January, Trump signed an executive order calling for the "immediate construction of a border wall" with Mexico that he insisted the country will pay for.

"In the social and civil context as well, I appeal not to create walls, but to build bridges," the pontiff said. "To not respond to evil with evil. To defeat evil with good, the offence with forgiveness. A Christian would never say 'you will pay for that.' That is not a Christian gesture. An offense you overcome with forgiveness. To live in peace with everyone."

Last year, the pope made similar comments regarding walls and building bridges when Trump was still a presidential candidate.

"A person who thinks only about building walls, wherever they may be, and not building bridges, is not Christian," Francis tweeted. Trump quickly shot back saying: "For a religious leader to question a person's faith is disgraceful."

The president has not yet responded to Pope Francis' latest tweets.