A state of emergency has been declared in four southern US states with Hurricane Nate gathering strength as it heads towards the Gulf Coast. <br/><br/>Louisiana, Mississippi, Alabama and parts of Florida have issued hurricane warnings and evacuation orders. The measures apply to parts of the city of New Orleans, which was devastated by Hurricane Katrina 12 years ago.<br/><br/>Nate killed at least 25 people as it swept through Nicaragua, Costa Rica and Honduras as a tropical storm. The storm, which brushed past Mexican beach resorts, is still strengthening, and is now expected to make landfall as a category two hurricane overnight. <br/><br/>Although not as strong as last month's Maria and Irma, Nate will still bring strong winds and storm surges.<br/><br/>Its latest recorded wind speeds reached 150 kilometre per hour. US President Donald Trump has issued an emergency declaration for Louisiana, allowing the state to seek federal help with preparation and possible relief efforts.<br/>'<br/>In Alabama, Republican Governor Kay Ivey has urged residents in areas facing heavy winds and storm surges to take precautions. Five ports along the Gulf Coast have also been closed to shipping as a precaution.