Rain and wind gusts from the outer bands of tropical storm Emily struck Puerto Rico on Tuesday as the storm system gathered strength on a track that threatened the Dominican Republic and Haiti, where more than 600,000 people are still without shelter after last year's earthquake.

The rain fell hardest in western Puerto Rico, largely sparing the capital, but there were no reports of major damage or injuries and no immediate demand for the nearly 400 schools that were converted into emergency shelters around the island. Emily had been expected to bring up to15 centimetres to the island.

Gov. Luis Fortuno declared a state of emergency and most government offices were closed. Ahead of the storm, people cleared water and other emergency supplies from store shelves and tourists fled the small Puerto Rican islands of Culebra and Vieques.

With the storm more than 320 kilometres to the south in the Caribbean Sea, most of the island saw no more than sporadic gusts and showers. But the National Weather Service said up to 13 centimetres of rain had fallen in the Cabo Rojo-Mayaguez region in the island's west.

One regional airline, LIAT, cancelled flights but otherwise activity was normal at the airport and throughout most of the capital.

"It's no big deal," said Peter Morris, a 23-year-old University of Indiana student visiting the island. "I'm going to surf the day away and party all night long here, in this beautiful island."

Haiti and the Dominican Republic prone to floods

The U.S. National Hurricane Center said the storm, which had been almost stationary in the morning, was on a west track at 22 kph by early evening. The path would bring Emily's centre over Hispaniola, the island shared by Haiti and the Dominican Republic, by Wednesday evening or Thursday. Both countries, but especially Haiti, are prone to devastating floods.

Early Tuesday evening, the storm was about 265 kilometres south of San Juan, Puerto Rico. It had maximum sustained winds of 85 km/h. U.S. forecasters said some slight strengthening was possible before the storm's centre passed over the mountains of Hispaniola.

Civil defence officials and the military in the Dominican Republic have already begun moving people out of high-risk zones ahead of the storm. Haitian authorities urged people to conserve food and safeguard their belongings.

'We receive these messages and yet we still don't have anywhere to go.' —Alexis Boucher

In Haiti's capital of Port-au-Prince, Jislaine Jean-Julien, a 37-year-old street merchant displaced by the January 2010 earthquake, said she was praying the storm would pass her flimsy tent without knocking it over.

"For now, God is the only saviour for me," Jean-Julien said at the edge of a crowded encampment facing the quake-destroyed National Palace. "I would go some place else if I could but I have no place else to go."

Haitian emergency authorities set aside a fleet of 22 large white buses in the event they needed to evacuate people from flooded areas. Emergency workers would then bus the people to dozens of schools, churches and other buildings that will serve as shelters.

"We're working day and night to be able to respond quickly in case we  have any disasters," said Marie Alta Jean-Baptiste, director of Haiti's Civil Protection Agency.

Emergency workers, both Haitian and foreign, also sent out text messages to cellphone users, alerting them to the approaching storm and to take precautions such as staying with friends or relatives if that were an option.

Such advisories are not uncommon but few in Haiti have the means to heed them because of the crushing poverty.

"This is not the first time we've heard these messages," said Alexis Boucher, a 29-year-old man who lives in Place Boyer, a public square that became a camp after the earthquake. "We receive these messages and yet we still don't have anywhere to go."

UN notifies troops

The United Nations peacekeeping force in Haiti notified its 11,500 troops to be on standby in case they need to respond, said Sylvie Van Den Wildenberg, a spokeswoman for the UN peacekeeping mission. The International Federation of Red Cross and Red Crescent Societies, too, put emergency teams on standby, who have access to relief supplies already in place for up to 125,000 people in seaside towns throughout the country.

In the Dominican Republic's southern tourist districts, workers at hotels and restaurants gathered up umbrellas, tables, chairs, and anything else that might be blown away.

Capt. Frank Castillo, dock master of the Marina Casa de Campo in the southeastern tourist city of La Romana, and his crew helped boat owners secure their vessels in slips or pull them ashore.

In the U.S. Virgin Islands, the government said it would not open emergency shelters on Tuesday afternoon since storm tracking information indicated that the U.S. territory would not get hit by damaging winds or heavy rainfall.

So far, the storm had not caused major problems passing through the Caribbean, just minor ones. It forced the postponement until the weekend of the annual Carnival parade and caused mudslides and local flooding in Dominica.

A tropical storm warning was in effect for Puerto Rico, Vieques, Culebra, the Dominican Republic and Haiti. A tropical storm watch was in effect for the U.S. Virgin Islands, the southeast Bahamas, and the Turks and Caicos Islands.