The United States has condemned what it says is Sudan's “heavy-handed” crackdown against anti-government protests that have spread through several parts of the East African nation.

The protests began in the capital, Khartoum, nearly two weeks ago as isolated student protests over planned government austerity measures and sharp price increases.

The unrest has quickly spread into larger and more volatile demonstrations throughout the capital and several other parts of the country. Sudanese security forces have responded harshly, using tear gas and batons on protesters, who have responded by throwing rocks and burning tires in the streets.

U.S. State Department spokesperson Victoria Nuland said Tuesday there have been reports of protesters being “beaten, imprisoned and severely mistreated while in government custody.” Nuland said the crackdown on protesters will not solve Sudan's economic crisis. She called for Sudan to immediately release all of those detained.

Human Rights Watch is also speaking out against the Sudanese government's response to the unrest. The New York-based group said in a report Tuesday that security forces have arrested “scores” of protesters, opposition members, and journalists. It also said rubber bullets and live ammunition have been used to break up what it says are peaceful protests.

Sudanese President Omar al-Bashir has dismissed the protests as the work of a few isolated agitators, denying that they amount to a Sudanese version of an “Arab Spring.” Sudanese officials have also resisted calls to reinstate a government subsidy that had kept the price of fuel low in Sudan.