A gas explosion killed at least 10 people and injured more than 250 on Monday, authorities said, when a tank that fell from a crane released a poisonous yellow cloud at Jordan's Aqaba port.
Footage on state-owned Al-Mamlaka TV showed the large cylinder, said to have been carrying about 30 tonnes of gas, plunging from a crane on a moored vessel, causing a violent release of the gas cloud.
The force of the blast sent a truck rolling down the harbourside, while port workers could be seen running for their lives.
The death toll rose to 10, government spokesman Faisal al-Shaboul told AFP, revising an initial toll of five killed.
Civil defence spokesman Amer al-Sartawy reported that 251 people were injured.
"Specialists and the hazardous substances team in the civil defence are dealing" with the incident, Sartawy added.
Trucks were seen lined in a row carrying similar containers at the time the accident occurred.
Nearby areas were evacuated and residents told to stay indoors.
Prime Minister Bishr Khasawneh and Interior Minister Mazen al-Faraya headed to the site of the incident, state media reported.
The deputy chief of the Aqaba Region Ports Authority, Haj Hassan, told Al-Mamlaka that an "iron rope carrying a container containing a toxic substance broke, resulting in the fall and escape of the poisonous substance".
The channel also cited the former head of the company that operates the port, Mohammed al-Mubaidin, as saying that a vessel had been waiting to load almost 20 containers of liquified gas "containing a very high percentage of chlorine".
He nonetheless added that the gas is heavy and "it is not easy for its gas clouds to move... as it concentrates in one area and is affected by wind movement".
According to Jordanian official sources the southern beach of Aqaba, a Red Sea resort area, was evacuated following the incident.
The leak was unlikely to reach neighbouring Israel, a spokeswoman for that country's environmental protection ministry said, noting that there was a "northerly wind blowing now indicating that the gas would not affect the residents of Eilat and the area, (but) rather Saudi Arabia".
The injured were transported to two state hospitals, one private facility and a field hospital.
Local media showed members of civil defence forces, some dressed in hazmat suits, as well as medics rushing to the scene clad in masks.
Aqaba health director Jamal Obeidat said that hospitals were full in the area and "cannot receive more cases".
"The injured people are in medium to critical condition," he added.
He called on residents of Aqaba to "stay in their homes and shut all windows as a precaution", stating that the chemical substance is very dangerous, without specifying what it was.
"The government formed a team headed by the interior minister to investigate the accident and take the necessary measures," al-Shaboul said.
The government spokesman urged citizens not to approach the site of the incident, adding that medical reinforcements were being sent to Aqaba.
Israel expressed its condolences and offered to help.
"As we've told our friends in Jordan, the Israeli defence establishment is ready to assist with any effort, by any means necessary," Defence Minister Benny Gantz said.
Jordan's Aqaba port is the country's only marine terminal and a transit point for a vast portion of its imports and exports.