Sierra Leone has banned the country's bank workers, tax officers and some shipping officials from travelling abroad without permission in a wide-scale crackdown on tax fraud.
Authorities in the West African state have arrested 13 people working in banks and the tax authority as part of an investigation that has underscored deep-rooted corruption in a country attracting investment as it recovers from years of war.
"If they go to the airport, they will have to produce clearance from the police department," Ibrahim Koroma, head of Sierra Leone's Criminal Investigations Department, told Reuters.
Koroma said the travel restrictions would remain in place "until we're satisfied that all the people we need to contact in this investigation have been contacted".
"We're mindful of people's human rights, so we hope to have it finished as soon as possible," he added.
The probe has also targeted 28 shipping and clearing agencies over concerns goods entering and leaving the country are not being fully declared to customs officials.
Senior government officials in Sierra Leone have been accused of corruption over the past few years and the Anti Corruption Commission faces accusations of failing to follow through on cases despite some recent successes.
Earlier this month, two Finance Ministry employees became the first government officials to be jailed on corruption charges, while the indictment of 29 state employees in March marked the body's biggest move to date.
Sierra Leone's iron ore deposits have attracted billions of dollars in investment but it was suspended by industry watchdog the Extractive Industries Transparency Initiative which said transparency requirements had not been met.