South Korea's defense ministry says there are no signs of any surviving sailors out of the 46 still missing three days after their ship, the Cheo-nan, sank. And the country's defense minister, says the DPRK may have intentionally floated a mine to damage a naval ship.

South Korean Navy's Ship Salvage Unit members search for survivors from the sunken South Korean navy ship near South Korea's Baengnyeong Island on Monday, March 29, 2010. The 1,200-ton Cheonan, exploded and sank near the tense maritime border with North Korea late Friday.

Military officials say time is running out for any of the navy crewmen who might still be alive and trapped inside the Cheonan.

The ship has dozens of waterproof cabins. Authorities initially said that if crew members shut the doors quickly enough, some may have survived in the sunken vessel.

However, the supply of oxygen in the cabins was estimated to last up to 69 hours, a deadline that passed Monday night.

Meanwhile, divers at the wreckage of the ship got no response from those trapped.

Won Tae-Jae, spokesman of ROK Defense Ministry, said, "Our diving team informed us that they tapped on wall of the rear part of the sunken ship with a hammer, but there was no response. The team also knocked on the front of the sunken ship, but there was no response from that part either."

While the cause of the explosion is unknown, Defense Minister Kim Tae-young says the DPRK may have floated a mine toward the ship.

However, he added that there was no sign of actual attack from the DPRK, and admitted that the explosion could have been caused by a mine placed during the Korean War.

The DPRK has made no mention of the ship.

Meanwhile, families of the missing at the Pyeongtaek naval base are still hoping for a miracle..

Kyung-Ok Jung, wife of missing naval crew member,said, "They say no to everything and only give excuses. The president said he will send all military forces to save the missing people but it doesn't seem like it's happening."

But no news of the missing and a number of failed rescue attempts frustrated angry families.

A commanding officer tried to calm them, explaining the rescue operation could only take place when conditions allowed.

Rough waves and high winds over the weekend prevented military divers from gaining access to the wreckage.