The United States has put a $350 million aid package to Malawi on hold, following deadly clashes between police and protesters in the southern African country.

A U.S. government agency that assists developing countries, the Millennium Challenge Corporation, said Tuesday it will review its partnership with Malawi.

The agency has expressed concern about the government's use of force and restrictions on media reporting of the demonstrations. It said the developments call into question Malawi's commitment to good governance.

Protest organizers said Tuesday they will hold more demonstrations beginning August 17 if the government does not improve conditions in the country.

At least 18 people were killed last Wednesday and Thursday as police battled street protesters in three Malawian cities.

Authorities said at least 100 people appeared in Malawi courts on Tuesday to face charges related to the demonstrations, including arson, looting and theft.

The demonstrators were protesting fuel shortages, rising prices and what they say are eroding civil liberties.

President Bingu wa Mutharika characterized the demonstrations as an attempt to overthrow his government, and has vowed to hunt down the leaders of the protests. He named the head of the opposition and Malawi's vice president as suspected organizers.

The Millennium Challenge Corporation is designed to reward developing countries that protect human rights and practice the rule of law.

Britain recently cut economic aid to its former colony in the wake of a diplomatic disagreement. The dispute began after Mr. Mutharika deported Britain's envoy for describing the president in a leaked cable as “autocratic and intolerant.”