Kenya has suspended exports of khat to Somalia. Somali Kenyan consumers rely heavily on imports of khat.
In Kenya, the price of khat bag rose to $600, which is twice what it cost until recently, said a trader at the BBC.
He said the Somali government, for its part increased 100% tax on imports of khat, $200 for each bag.
The cultivation of this plant is a source of income for more than six million small farmers in Kenya. Each year, they earn about US $ 100 million.
The leaves of the plant are chewed for their stimulating and euphoric effect, comparable to that of amphetamine.
A law prohibiting the importation of khat was approved by the British Parliament in May 2014.
According to the Minister of the Interior, the ban was necessary to prevent Britain becoming a hub for khat traffic.
At least 40 tons of khat pass weekly by Southall, an industrial area near Heathrow International Airport in London.