Churchgoers should wear face coverings and may have to book places at Mass when churches reopen, Scotland's Catholic Bishops have said.
The Bishop's Conference of Scotland has sent the country's 600 priests guidance about the resumption of public worship.
They have been encouraged to start preparations to allow churches to safely reopen with social distancing.
Priests are being told to "act in harmony" with Scottish government advice.
The Catholic church's guidance has been developed by its Covid-19 infection control working group, chaired by Scotland's former chief medical officer Sir Harry Burns.
'Only open if safe to do so'
In line with the Scottish government's "route map" for easing lockdown, the guidance stresses that Mass can resume once the country enters phase three, with the recommendation to have services on both Saturdays and Sundays to allow more people to attend.
Priests are being asked to measure the church in two-square-metre areas to estimate how many people can safely attend services, but are reminded they should only open if there is enough trained volunteers and PPE available.
In parishes where demand for places exceeds the restricted capacity of the church, the advice suggests "it may be advisable to introduce a booking system for places at Mass, either online or by phone".
'Sermons should be brief'
Further guidance includes requiring all churchgoers to wear face coverings, and use hand sanitiser when entering and leaving.
Liturgical guidelines for Mass state that Holy Communion wafers should be placed in a person's hand, rather than their mouth, hymns may be omitted and "sermons should be brief".
The letter from the eight Scottish Bishops to priests accompanying the guidance says: "Our aim is to act in harmony with the guidance of the government and the health authorities, with whom we are in conversation, and to return to our normal liturgical and devotional practice in a safe and phased way."
The letter continued: "It is important that we act together as the Catholic Church in Scotland, in step with one another, and clear about what is legitimate and prudent at each stage of the process."
It adds: "Happily, as the virus abates and restrictions are eased, we can begin to move firmly and sensibly towards the reopening of churches and the resumption of public worship.
"We look forward eagerly to the day when it will be possible to gather again, without fear, around the altar and celebrate the Holy Eucharist together."