DUBAI (Reuters) - Amnesty International accused pro-government Yemeni troops battling Houthi forces for control of the southwestern city of Taiz of harassing medical staff and putting fighters among the civilian population, in charges the authorities strongly denied.

Civilians in Taiz, which had a pre-war population of 300,000, have been trapped by intense fighting, with dead bodies lying in the streets and hundreds of people wounded this week, the International Committee of the Red Cross said on Tuesday.

Amnesty, a London-based human rights watchdog, said that so-called Popular Committees - anti-Houthi local militias backed by exiled President Abd-Rabbu Mansour Hadi's government - had detained and threatened to kill medical staff in Taiz and deployed tanks outside hospitals.

Popular Committee fighters hold most of Taiz, Yemen's third largest city, but are hemmed in by Houthi forces on three sides.

"There is compelling evidence to suggest that anti-Houthi forces have waged a campaign of fear and intimidation against medical professionals in Taiz," said Philip Luther, research and advocacy director at Amnesty's Middle East and North Africa wing.

"By positioning fighters and military positions near medical facilities they have compromised the safety of hospitals and flouted their obligation to protect civilians under international law."

Deputy Human Rights Minister Nabeel Abdulhafeedh Majed said the report was biased and contained factual errors. He said pro-government "Resistance Forces" had no tanks in Taiz, adding that it was the Houthis who were besieging the city and terrorizing civilians.

"Even if some isolated incidents of revenge by individuals in the Resistance had happened in the past, this is no longer the case," Majed told Reuters by telephone from Cairo.

"The national army has brought matters under control and army officers now lead the resistance in a professional manner," he added.

A Saudi-led coalition has been fighting the Houthis since March 2015 to restore the internationally recognized Hadi, who is living in exile in Saudi Arabia.

The United Nations has also accused Houthi forces around Taiz of blocking humanitarian supply routes into the city, located some 205 km (123 miles) south of the capital Sanaa.

Rights groups have accused both sides in Taiz of using rockets and mortars in populated residential areas. Landmines planted by Houthis in Taiz have caused numerous civilian casualties, according to Human Rights Watch.

Amnesty said its researchers had interviewed 15 doctors and other hospital staff in Taiz who described how Popular Committee members had "regularly harassed, detained or even threatened to kill them over the past six months".

The report cited at least three cases in which hospitals were closed after threats to staff, including an incident on Monday when fighters shut down the biggest public hospital apparently for providing emergency medical treatment to three injured Houthis.

The report quoted the director of the hospital as saying fighters had set up positions and tanks around the compound, ignoring pleas from staff and local authorities not to do so.

(Reporting by Sami Aboudi; Editing by Mark Heinrich and Hugh Lawson)