BEIJING, June 2 -- A passenger ship carrying 456 people sank in the Yangtze River overnight, in what could be China's worst sinking disaster in decades.

The following are some key facts about the accident.

1. CASUALTIES SO FAR

As of 9 p.m. Tuesday, 14 people have been rescued and seven were confirmed dead, according to the latest counting by the Ministry of Transport.

About 430 others remain unaccounted for.

Rescuers said there could be more survivors in the upturned wreckage.

2. HIT BY TORNADO?

The captain and chief engineer, who both survived the incident, said the ship was caught in a tornado on Monday night in Jianli, Hubei Province.

Their words were echoed by experts with the China Meteorological Administration (CMA), who said a tornado with winds of at least 110 kilometers per hour, that lasted 15 to 20 minutes, was recorded at the time of accident.

3. WHAT HAPPENED BEFORE SINKING?

Many passengers had retired to bed around 9 p.m. Monday, when a storm began, said Zhang Hui, a tour guide from Shanghai who was rescued on Tuesday Morning.

Twenty minutes later, the ship began to tilt. Zhang said when he was picking up fallen objects he was hit by an eerie feeling of foreboding. Then the ship capsized.

It all happened within a minute, he said.

4. MOST PASSENGERS WERE OVER 50

The ship was carrying 405 passengers, five tour guides, and 46 crew. Most were tourists from Shanghai and its neighboring province of Jiangsu, aged between 3 and 83, the majority were in their 60s and 70s.

5. HOW IS THE RESCUE GOING?

Chinese President Xi Jinping has despatched a State Council work team to the site to guide the search and rescue work, and ordered all-out efforts. Premier Li Keqiang is at the scene.

More than 4,000 rescuers, including police, fire fighters and soldiers from the Chinese Navy, are battling strong winds and heavy rain to search for the missing.

Divers will continue to comb the ship for survivors, while the search will expand to the nearly waters.

6. ABOUT THE SHIP

The 76-meter-long vessel has been in service for nearly 20 years and can carry up to 534 people.

Local authorities said the ship was an ordinary passenger ship, not a luxury cruise liner.

7. CAPTAIN DETAINED

The ship's captain and chief engineer are in police custody.