Hijacked Chinese bulk carrier De Xin Hai is seen in this picture published on the European Union Naval Force Operation Against Piracy website and taken October 19, 2009 by an EU NAVFOR Maritime Patrol Aircraft off the East coast of Somalia. [Agencies]

China said on Tuesday it will "make every effort" to free the crew of a cargo ship held by Somali pirates in the Indian Ocean, something experts said will be best done through bargaining and diplomatic efforts.

The De Xin Hai ship and its 25-member crew was carrying about 76,000 tons of coal on its way from South Africa to the port of Mundra, in Gujarat, India, when it was seized by pirates about 700 nautical miles off the Somali coastline on Monday.

The hijacking happened about 1,000 nautical miles away from a fleet of Chinese warships escorting merchant vessels through the waters.

Foreign Ministry spokesman Ma Zhaoxu said Tuesday the government had launched an "emergency response procedure" in the wake of the hijacking and instructed Chinese embassies and consulates to gather and review information about the incident.

It has also issued warnings to Chinese ships to stay away from the area.

Ma said China will "watch closely developments and make every effort to rescue the crew and carrier".

On Monday, the European Union's counter-piracy force said an EU maritime patrol aircraft had located the vessel and counted at least four pirates on the deck. The ship is now heading northwest and is now 650 nautical miles off the east coast of Somalia.

Daniel Auwermann, an official of the organization's media center, said the ship is expected to head toward pirate strongholds based in Somalia.

China's Central Television reported that phone calls the ship owner made to the ship and faxes were not responded to.

The pirates are likely to contact the owner of the ship after they arrived in Somalia and obtained supply, Auwermann said.

Experts estimate that a reponse from the hijackers will probably come in two days' time when the pirates have taken the ship to a place where they fell in control.

China's maritime safety administration said it was coordinating with international maritime agencies to send the escorting fleet into the region to be ready to mount a rescue operation.

The company that owns the De Xin Hai, which is based in eastern Shandong province, said on Tuesday it had notified the relatives of the 25 crew about the hijacking.

Twenty-two members of the crew were from Shandong and the other three were from Liaoning, Hebei and Jiangsu provinces, a company spokesman told Xinhua.

The last time a Chinese ship was attacked by pirates was in December. So far, no casualties have been reported from the latest incident.

The pirates threatened Tuesday to execute the 25 Chinese crew members if a rescue operation was mounted.

"We tell China not to endanger the lives of their people with any rescue operation," Hassan, an associate of the gang, told Reuters by phone from the pirate stronghold Haradheere.

De Xin Hai could be brought to Haradheere, or Hobyo, both in the central portion of Somalia's coastline, Reuters was told.