Washington  - Residents along the Texas coast were evacuating on Thursday as Hurricane Ike took aim at the US mainland.

Ike, a category two storm on the five-level Saffir-Simpson scale, with 160 kilometre per hour winds could strengthen into a major category three hurricane before making landfall late Friday, the US National Hurricane Centre in Miami said.

Thursday morning the storm was about 760 kilometres east-southeast of Galveston, Texas. Forecasters said Ike was "a very large tropical cyclone" and would bring high tides and strong winds before the storm itself reaches the coast.

Officials in the Houston area had called for evacuations of low- lying areas and mandatory evacuations were underway in other coastal areas, including the popular beach resort of Galveston, the Houston Chronicle newspaper reported.

The storm could test the state's emergency plan that was revamped in the wake of Hurricane Rita in 2005, when evacuees clogged highways and drained petrol stations bringing the state to a standstill, the newspaper said.

The National Hurricane Centre said storm surge flooding could bring tides up to 6 metres above normal levels and dangerous waves. Ike could also dump from 13 to 25 centimetres of rain along the Texas and Louisiana coasts.

Texas Governor Rick Perry had declared 88 counties disaster areas to free up funds to respond to the storm. Up to 7,500 members of the Texas National Guard were preparing for the landfall and the state had set aside thousands of buses to take evacuees inland.

US space agency NASA closed its Johnson Space Centre in Houston, moving operations to back-up facilities and flying aircraft to another site. (dpa)