Worship services were held outside churches in the U.K. last Sunday in an effort to draw attention to the persecution of Christians across the world.

The outdoor services were part of an annual campaign organized by U.K.-based Release International called Great Outdoors Church Service.

"Choosing to meet outside come rain or shine really brings home how precious our freedoms are," said Release International CEO Paul Robinson, according to a news release from the group.

"Taking time out to pray for the persecuted can spur us on to use our freedom to the full," he added.

Andrew Boyd, a spokesperson for the group, is encouraging more churches to participate in the campaign, which aims to raise awareness about Christian communities that are being pressured to meet in secret due to persecution from hostile governments.

"We have amazing freedom in this country to do whatever we like really without the risk of persecution. It's ever so easy to take that freedom for granted, so why don't we just take a very small risk; the really small risk is that it's probably going to rain but never mind," Boyd has said.

As part of the campaign, participating congregations are encouraged to consider making use of their freedom to support other believers who are being persecuted for their beliefs.

The charity suggested that the campaign could be held on May 27, but it stressed that any date is suitable to hold outdoor services.

Release International noted that persecution against Christians continues under Islamic rule, militant Hinduism, and communist regimes.

The organization pointed to Christians often being accused of blasphemy in Islamic countries such as Pakistan. It argued that blasphemy laws are being used as a way of settling scores and expelling Christian minorities.

Another example cited by the group was the demolition of churches and crosses in China. The charity also noted that North Korea has been considered as the most hostile place in the world for believers.

Robinson said that setting aside a single day each year to hold outdoor services is a great way to stress the importance of standing in solidarity with persecuted Christians.

He noted that outdoor services give congregations in the U.K. a "taste of what it's like for believers who have neither the comfort nor security of meeting in a building."

Release International, which supports Christians in over 30 countries, is celebrating its 50th anniversary in 2018. The group was launched in 1968 by Pastor Richard Wurmbrand, who was imprisoned and tortured for his faith in Romania when the country was under communist rule.