Azerbaijan was on Sunday searching for 29 missing oil workers after a storm caused their offshore oil rig to catch fire, as the president ordered a day of mourning.

A fire broke out on the rig in the Caspian following a storm on Friday "leading to many deaths," said a statement on the official website of President Ilham Aliyev.

"I join the relatives in their grief and designate December 6 as a day of mourning in Azerbaijan," it quoted him as saying.

The statement was the closest to an official confirmation that 30 workers may have perished at sea when one lifeboat where the crew was taking refuge fell into the water.

Rescue workers had lifted a total of 33 people from the rig, the open water, and from a lifeboat that was suspended 10 metres (35 feet) above the stormy waters.

But the second lifeboat fell into the water and has not been recovered.

So far, one worker's body has been recovered.

On its Facebook page, SOCAR listed the 62 names of those working on the rig, who were either rescued or missing.

"We are looking for 29 people. Whether they are alive or dead we don't know. Before we find them we cannot pronounce them dead," SOCAR vice-president Khoshbakht Yusifzade told journalists at a press conference on Sunday.

- Safety inquiry opened -

The storm had on Friday damaged a gas line on platform number 10 in the deepwater Guneshli section of the Azeri-Chirag-Guneshli offshore oil field, causing a fire, SOCAR said.

Prosecutors on Saturday opened an inquiry into possible "breaches of fire safety regulations".

The Guneshli deposits were discovered in 1981 in the south Caspian Sea, some 90 kilometres (55 miles) east of the Azeri capital Baku.

The deepwater Guneshli section of the project began oil production in 2008. Platform number 10 is operated solely by SOCAR.

A mainly Muslim country of nine million wedged between Russia and Iran, Azerbaijan is a key partner in projects to deliver Caspian Sea energy reserves to the West through pipelines to Turkey, bypassing Russia.

There have been a number of fatal incidents on offshore oil rigs in recent years.

In 2011, a drilling platform sank in a storm off Russia's far eastern coast, killing 53 people.

In 2010, an explosion on the BP-leased Deepwater Horizon rig killed 11 workers and sent millions of barrels of oil spewing into the Gulf of Mexico.

The deadliest incident in recent decades occurred in the North Sea in 1988, when the Piper Alpha oil platform operated by the US-based Occidental Petroleum exploded, killing 167 people.
Source: AFP