Three high-ranking police officials in the Dominican Republic have been accused of providing security to drug traffickers, marking the latest public corruption case to hit the Caribbean nation as it tries to clean up its military and police.

The officials worked for the National Drug Control Agency and were arrested alongside four men allegedly waiting for a drug shipment bound for Puerto Rico, agency chief Rolando Rosado said Thursday.

The officials have been suspended from their jobs as have others who have been charged in drug-fueled corruption cases that have resulted in dozens of arrests and dismissals in recent years.

"It's a serious situation," said Tulio Castanos, vice president of the Institutional Justice Foundation, a non-governmental group that is helping the government design and implement police department reforms. "The people have lost faith in the police."

The Dominican Republic has a national police force of 32,000 officers and a military with 65,000 members, for a country of about 9 million people.

Since 2009, more than 700 agents with the National Drug Control Agency, a combination of police officers and military personnel on loan, have been removed for a variety of crimes, according to government statistics. Of those, 200 were suspected of involvement in drug trafficking.

Meanwhile, the national police force has expelled about 1,400 officers since 2010 for a variety of alleged crimes, including ties to drug trafficking, spokesman Maximo Baez said.

Members of the police and all branches of the military have become ensnared in drug investigations, including a recent one involving a navy officer in charge of port security accused of attempting to smuggle more than 800 kilograms (1,760 pounds) of cocaine to Spain on board a cargo vessel.

In another case, nearly 20 officials, the majority with the navy, were accused in 2008 of killing seven Colombian drug traffickers to steal 1.3 tons (1.18 metric tons) of cocaine. Five of those officials were sentenced to 30 years in prison, while three others received 20-year sentences.

So far this year, authorities have confiscated more than 4 tons (3.6 metric tons) of cocaine. They seized nearly 7 tons (6 metric tons) during all of 2011.

"The biggest concern is that in almost every seizure, officials were implicated," according to a report by Citizen Involvement, a non-governmental organization that tracks corruption allegations in the Dominican Republic.

The government is now requiring members of the police and armed forces to pass polygraph and background tests. In addition, internal affairs units are regularly investigating corruption allegations and handing out punishments, which has been increasing along with the country's role as a stepping stone for cocaine and other drugs bound for the U.S. and Europe.

The government's attempt to address the situation comes amid growing concerns among Dominicans about the way drug trafficking has seemed to take a central role in the country.

But there is also pressure from the U.S., which was critical of Dominican anti-drug efforts in its annual 2012 trafficking report.

In a 2009 diplomatic cable obtained by WikiLeaks and other organizations, the U.S. Embassy in the Dominican Republic noted the country had an "embarrassing" drug seizure rate and cited a lack of resources for law enforcement and infiltration of the armed forces by criminal organizations.

Former President Leonel Fernandez and others also have cited low salaries, typically around $155 a month for police officers, as a long-standing problem that may be a factor in some corruption cases.

Complaints that police and military officials demand payment from drug traffickers to operate in certain neighborhoods are common, said Manuel Maria Mercedes, president of the National Commission of Human Rights.

Payments can range from $125 a week in poor communities to more than $1,000 a week for drug-distribution points in popular tourist regions, and shootouts ensue if they fail to pay, he said.

"Hundreds of citizens have lost their lives this way," he said.