President John Magufuli told Tanzania's security forces on Monday to crack down on the drug trade and said no one should be spared, even if they are top politicians or their relatives.
Magufuli, nicknamed "The Bulldozer" for the way he pushes through projects, has launched a drive against corruption, tax evasion and poaching since taking office in November 2015.
His new drive against drugs reflects growing international concerns that East Africa is being used by traffickers.
While most Europe-bound Afghan heroin still goes through Iran and the Balkans, a spate of record-size hauls near Kenya and Tanzania has raised fears that East Africa is seen as an easier route because of porous borders and weak maritime surveillance.
"In this war against narcotics, no one is too prominent to be arrested even if they are politicians, security officers, cabinet ministers or the child of a prominent person," Magufuli told the heads of the defense and security forces.
In his speech at the presidential State House, he said that "even if my wife, Janeth, is involved," she should be arrested.
Tanzanians have long complained that top officials or those with government connections have often been spared prosecution for corruption and other crimes.
Magufuli has sought to show even those in high office will be held accountable for criminal activity or poor performance.
He has sacked several top officials in the tax authority and other institutions since taking office.
On Monday, he praised the police chief for suspending 12 junior officers last week on suspicion of drug trafficking.
But he said the campaign must target the financiers and dealers, citing the case of one unnamed drug trader whose case was taking too long to go through the courts.
"I know some leaders tried to defend him. But we must now start to jail these big drug dealers, instead of just dealing with the little people," the president said.