The call to avoid places of worship comes as Sri Lanka enters the first weekend of religious services following Sunday's mass bombings.
Ahead of Friday's dawn prayers, Muslims were asked not to gather publicly for the congregational Friday prayer service -- known as the Jum'ah prayer -- according to a statement labeled "very urgent" on Thursday by Sri Lanka's Minister of Postal Services & Muslim Religious Affairs Mohamed Hashim Abdul Haleem.
"As a sign of solidarity with the Catholic Community and a show of protest again the Barbaric act of the ruthless terrorists I appeal to my Muslim brothers to refrain gathering for congregational prayers tomorrow (Friday), but to pray in the homes instead, for peace and security of our motherland," said Haleem.
The Minister's statement called for prayers to end the actions of the "inhuman terrorist murderers," and offers condolences to the victims targeted in churches and luxury hotels, saying that the Muslim community "stand(s) with Christian brothers and sisters during their times of grief."
Driving through Colombo, a CNN reporter observed that shops that would normally be open at this time had been shuttered, and noted that security warnings broadcast on television and radio had spread fear.
According to a revised death toll, 253 people, including many worshipers attending Easter Mass services, died in the coordinated attacks.
Catholic services across Colombo have also been suspended -- until April 29 -- because of security concerns, according to Fr. Edmond Tillekeratne, media director of the Archdiocese.
The decision, which will see Catholic churches in the capital shuttered for services this Sunday, was made at the direction of Archbishop of Colombo, Cardinal Malcolm Ranjith.
Both Christianity and Islam are minority religions in Sri Lanka, each accounting for less than ten percent of the total population. According to census data, the vast majority of Sri Lankans identify as Buddhist.
Sri Lankan authorities are currently searching for "sleepers"—potential terrorists who could activate to initiate another round of attacks—Sri Lanka's Prime Minister Ranil Wickremesinghe told CNN on Thursday.
"Police and security forces are rounding up those involved, but they're also rounding up the sleepers, those used on second and third rounds (of attacks)," he said.
"The danger has come down drastically, (but) we do have to pick up some more sleepers, which we will do in the next few days."
He said security services were taking steps to ensure that no potential terrorist was on the loose, and said that a second wave of attacks was not likely "now" but a concern in coming months.
"It is a precaution that we are taking, we want to be sure we have everyone in," he said in the sit-down interview.
"They are worried that one or two could get into a church -- (even) one person can do a lot of damage."
National Tawheed Jamath (NTJ), a domestic extremist group, has been identified as the perpetrator of the Easter Sunday bombings, but has not claimed the attacks. While the terror group ISIS has claimed responsibility for the attacks, that link has not been proven.
Travel advisories amid heightened threat
Concerns over further attacks have moved several counties to warn their citizens to avoid the Indian Ocean nation.
Israel and the UK were the latest countries to issue travel advice, with Israel citing a "high concrete threat."
Its Counter-Terrorism Bureau issued a travel warning for Sri Lanka on Thursday, raising the threat level to its second-highest, and advising travelers already in-country to leave. The warning came after consultations with security and foreign ministry officials, according to a statement from the Counter-Terrorism Bureau.
They join the US, China, South Korea and Australia in issuing advisories amid ongoing threats to travellers' wellbeing in Sri Lanka.