Heavy rain has started to fall in the Haitian capital Port-au-Prince as a powerful storm approaches, threatening earthquake survivors¹ living in camps.

强风暴托马斯接近海地，首都太子港开始降暴雨，威胁到居住在帐篷中的地震幸存者。

The government has urged the 1.3 million people living in tented homes to find sturdier shelter, but most have stayed, saying they have nowhere to go.

Forecasters say Tropical Storm Tomas is gaining strength and warn of the danger of flooding and mudslides.

Health workers fear heavy rain will exacerbate²（加剧，恶化） Haiti's cholera³（霍乱） epidemic⁴.

The outbreak of the water-borne disease - which has so far killed more than 400 people and infected more than 6,700 in Haiti - has not seriously affected⁵ the capital, but aid agencies say flooding could change that.

Haitian President Rene Preval went on national radio on Thursday to urge people to take precautions（未雨绸缪） and evacuate⁶ the camps.

"Protect your lives," he said, before acknowledging that the authorities did not "have enough places [on buses] to move everyone".

The BBC's Laura Trevelyan in Port-au-Prince says few refugees have heeded⁷ the government warning, although mothers and babies have been evacuated⁸ from an exposed camp near the mountains.

Stefano Zannini, Medecins Sans Frontieres' head of mission in Haiti, described the situation as "precarious⁹（危险的） " and said destruction of tents would cause a new wave of homelessness.

He told the BBC that the atmosphere in the camps was "a mixture of fear and desperation - or resignation（辞职，放弃） ".

"It is the third big problem people here have had to deal with this year," he said.

Fear and confusion

Tomas is expected to make landfall in Haiti early on Friday. On Thursday afternoon, the storm was churning（搅拌） across the Caribbean about 450km (280 miles) west-south-west of the capital Port-au-Prince, with maximum sustained winds of 85km/h (50mph), the Miami-based National Hurricane Center (NHC) said.

The NHC warned of hurricane conditions - winds of 119km/h (74mph) or greater - for Haiti, the south-eastern Bahamas, the Caicos Islands and the Cuban province of Guantanamo.

It also issued a tropical storm warning for Jamaica and the Cuban provinces of Santiago de Cuba and Holguin.

Staff at the US Navy base at Guantanamo Bay in Cuba were clearing away debris¹⁰ that could fly around in strong winds, officials said.

In Jamaica, schools were closed in eastern areas and traffic was gridlocked（交通堵塞） in the capital, Kingston, as businesses closed early.

"On the forecast track, the centre will pass near Haiti or extreme eastern Cuba (late Thursday) and early Friday," the NHC said.

Tomas left at least five people dead in St Lucia over the weekend after hitting the eastern Caribbean as a hurricane.

The storm is expected to dump as much as 38cm (15in) of rain over Haiti and the neighbouring Dominican Republic, with more heavy rain over Jamaica and Cuba.

The UN said more emergency supplies and equipment were urgently needed.

"Even with the existing pre-positioned stocks, the potential magnitude（大小，量级） of this disaster urgently calls for additional emergency supplies and equipment," said Nigel Fisher, UN Humanitarian¹¹ Co-ordinator for Haiti.

Miloudy Vincent, a senior aide in Haiti's education ministry¹², said schools would close temporarily to be used as shelters.

At the Corail-Cesselesse relocation camp, fighting broke out on Wednesday when officials tried to explain a planned voluntary evacuation of nearly 8,000 people.

Many earthquake survivors worried that the authorities were trying to permanently¹³ move them out.

"We are upset because they have not told us where we are going," Domarcand Fenel, the head of a committee of camp residents, told the Reuters news agency. "People believe they want to expel（驱逐，开除） us."