Frustration mounted Wednesday over delays in returning to Galveston, the Texas coastal city hard-hit by powerful Hurricane Ike over the weekend, as the death toll caused by the storm continued to rise.

Ike killed at least 50 people in the 11 southern and midwestern states, CBS News reported. Of those, at least 30 were killed in Texas, according to local news media.

As of late Wednesday nearly two million people in the areas affected by Ike were in the dark, though power had been restored to more than a million households, Texas Governor Rick Perry said.

"Restoring power is a top priority now that search and rescue efforts are concluding," said Perry.

Search and rescue efforts along the Texas coast are nearly complete, Perry said, adding that more than 3,500 residents were rescued and some 28,600 structures searched.

Also Wednesday the US Coast Guard re-opened portions of the Houston Ship Channel to commercial traffic, with restrictions.

Galveston Mayor Lyn Ada Thomas on Wednesday urged people who chose to remain in the island-city when Ike struck to leave. Some 15,000 are believed to still be in Galveston.

"The medical and health concerns on Galveston Island are becoming more and more serious," she said.

Up to 300 people have been trickling out of the island each day since Ike struck, said Colonel John Nicols of the Texas National Guard.

Thomas said Tuesday that residents who show photo ID cards at highway checkpoints could return, but only to check on their property during daylight hours under a "look and leave" program.

However officials abruptly halted the program hours later due to "an overwhelming influx" of people, said Galveston City Manager Steve LeBlanc.

"We just simply cannot handle the volume of people," he said.

The change left thousands who fled Galveston ahead of the storm frustrated and confused, and created massive gridlock on roads leading into the city.

The island's only hospital, the University of Texas Medical Branch-Galveston (UTMB-G), was offering limited services, even though the number of patients seeking care had increased significantly over the past 24 hours, officials said.

"Like much rest of the island, we're standing but not very functional," said UTMB-G President David Callendar, adding that it could take up to two months for the hospital to be fully functional.

Texas health commissioner David Lakey said that Galveston patients needing serious medical attention will have to be airlifted to Houston.

"I still strongly feel that this island is not a suitable place for individuals to live," he said.

Stephen Pustilnik, the city's chief medical examiner, said that 16 bodies have been delivered since the storm hit, but of those only seven were storm-related deaths and the rest died of natural causes.

"They may be terminating the search for survivors but they haven't searched all the areas of the county for the deceased," he told AFP. "So we expect that number will change."