MADRID, Spain (CNN) -- Pirates who seized a Spanish fishing boat Sunday off the coast of Somalia have apparently demanded money for the release of the 26 crew members, Spanish state radio RNE said Monday.
RNE phoned the ship several times Monday and, in one of the brief conversations, a man who is apparently a pirate said, in English, that the demand was for "money," according to Ana Rosa Alonso, the master control room chief for RNE's all-news channel 5 in Madrid.
But a senior Spanish foreign ministry official told CNN that the government has not received any demands from the pirates.
Half the crew members are Spaniards.
A similar incident occurred earlier this month, when more than a dozen pirates seized a French yacht on April 4 off the Somali coast, holding its 30-member crew hostage for a week. No passengers were on board.
The hostages were freed, and six of the dozen or so pirates believed to have been involved are in French custody after a raid in the Somali desert.
In the latest incident, a Spanish senior foreign ministry official told CNN late Sunday that officials presumed pirates carried out the seizure of the Playa de Bakio tuna fishing ship.
Alonso said the man state radio spoke to claimed that there were four heavily armed pirates.
The foreign ministry official could not confirm the number of pirates involved but said there were no immediate reports of injuries, although the ship was damaged in the assault.
In another of state radio's calls to the ship, a man who said in Spanish that he's the captain of the ship assured listeners, "We are all all right and for the moment there's no problem." Then another man, apparently a pirate, interrupted the call and said in English, "bye bye, bye, bye."
A private radio network, SER, reports on its Web site that it had a brief conversation with another Spanish crew member, who pleaded with the radio not to call because the crew is being watched by the pirates.
U.S. and NATO warships have been patrolling off the Horn of Africa for several years in an effort to crack down on piracy off long-lawless Somalia, where a U.N.-backed transitional government and Ethiopian troops are now battling Islamist insurgents. The seizures have continued despite several run-ins between the pirates and the international fleet in recent months.
The incident with the Spanish ship occurred in an area known as "Somali waters," but the ship's distance from the Somali coast was not immediately known, the Spanish foreign ministry official said. It is an area where Spanish tuna boats typically fish, he added.
Spanish government statements said the Defense Ministry is sending a nearby ship to the scene of the hijacking, and has contacted Britain, France and other allies with military presence in the area. Spanish embassy is in Kenya, which also is responsible for Somalia, one statement said.
The Spanish deputy prime minister's office has created a crisis committee involving numerous ministries to handle the the situation.
Also Monday, an unidentified vessel shot at a Japanese supertanker off the Horn of Africa, but did not cause any injuries, the ship's owner said.
The crew of the 150,000-ton Takayama was assessing damage to the ship, according to a statement from the ship's owner, Nippon Yusen K.K. The ship was attacked about 440 km (255 miles) east of the Yemeni port of Aden en route to Saudi Arabia, the statement said.
Yemen's state news agency Saba blamed Somali pirates for the attack. E-mail to a friend