Somalia’s ban on Kenyan flights carrying the herbal stimulant khat has come into force, with no explanation as to why or how long it will be in place.
But the semi-autonomous region Puntland region is among some federal states defying the ban.
Khat is popular in Somalia but it is grown in Ethiopia and Kenya.
Hundreds of Kenyans, including farmers, could be affected by the decision, which has been criticised for coming without any warning.
BBC Somali Service editor Farhan Jimale says it is equivalent to a major city like London banning imports of alcohol overnight.
But as khat has to be taken fresh, there are no stockpiles.
The planes from Kenya arrive in Somalia’s capital, Mogadishu, in the morning and the leafy stimulant, which is not cheap, is usually chewed after lunch, mainly by men, in the afternoon and into the evening.
The BBC’s Ahmed Aden in Mogadishu says Civil Aviation Minister Ali Ahmed Jangali, who announced the ban on Monday, did not give a reason for the suspension, which is understood to be temporary.
He denied that it was because Somalia was hosting a meeting on Saturday for the regional body, Intergovernmental Authority on Development (Igad).
Workers at a khat-exporting company in Kenya’s capital, Nairobi, were told not to report to work on Monday.
Kenya’s government has in the past pledged to support the growers of khat after it was banned in much of Europe.
Khat is also banned in a number of other countries, including the US and Canada.