Kenya has given foreign business owners 90 days to obtain or update their legal documents.
The new period covers documents such as work permits and business licences.
The move follows concern among migrant communities after President William Ruto called for tighter rules on foreign-owned small businesses.
Kenya gives foreigners 90 days
Presidential spokesperson Hussein Mohamed said government agencies will work with foreign embassies during the process.
Foreign business owners will have three months to ensure their documents meet Kenyan requirements.
At the same time, Mohamed warned against threats, harassment and intimidation targeting foreigners.
The government says the registration process is designed to ensure compliance with Kenyan law.
It is also intended to follow East African rules covering the movement of goods, labour and services.
Ruto wants tighter rules for foreign businesses
The decision follows comments by President Ruto last week.
Ruto said he had received complaints from Kenyan small-business owners about competition from foreign traders.
He then directed lawmakers to expand legislation currently before parliament.
The proposed rules could identify some small-business sectors that would be reserved for Kenyan citizens.
Burundians seek documents in Nairobi
The uncertainty has particularly affected migrants from neighbouring countries.
Hundreds of Burundian nationals went to their embassy in Nairobi to obtain documents.
Some said they were considering returning home because they feared for their safety.
One Burundian businessman also told local journalists that his shop outside Nairobi had been attacked by unknown people.
He said he already had the correct licences.
Government warns against harassment
Kenyan officials have stressed that the new rules should not be used to target foreign residents.
Mohamed told a group of migrants that registration would also help authorities provide security.
Meanwhile, Burundi’s Foreign Minister Edouard Bizimana has publicly expressed concern about threats against Burundians living in Kenya.
Kenya is East Africa’s largest economy and attracts both investors and workers from neighbouring countries.
The 90-day period now gives affected foreign business owners time to bring their documents into compliance before tighter rules are enforced.