Pirates have hijacked another ship off the coast of Somalia, this time a Yemeni vessel carrying steel. As Derek Kilner reports from VOA's East Africa bureau in Nairobi, pirates have dropped their ransom on the largest ship in their possession - a Saudi Arabian oil tanker - to $15 million.

Pirates seized the MV Adina in the Gulf of Aden as it headed to the Yemeni island of Socotra, according to Yemen's official news agency. The ship was carrying over 500 tons of steel and seven crew members from Somalia, Yemen and Panama.

The ship had been scheduled to reach its destination last Thursday, and it was not clear when exactly the ship was seized. Yemeni officials said they have communicated with the pirates, who are demanding a ransom of $2 million.

Pirates currently hold over a dozen ships and over 200 crew members, off the coast of Somalia. Pirates captured the biggest vessel yet on November 15, the Sirius Star, a Saudi Arabian tanker carrying $100 million worth of oil.

A man who identified himself as a pirate aboard the ship told VOA by telephone that the pirates had reduced their ransom demand for the tanker from $25 million to $15 million, in line with earlier media reports.

NATO has four warships in the area, and the European Union, along with Russia and India, have committed naval vessels to deal with the problem. Germany announced on Tuesday that it was willing to send 1,400 troops to join the E.U. mission, which is set to begin in December.

The head of the U.S. military's Africa Command, or Africom, General William Ward, who is Nairobi for meetings with Kenyan officials, said the United States is concerned about the rise in piracy, and is involved in multilateral efforts to provide security, but that the issue is not a primary focus for Africom.

"The United States is participating in those activities currently, but again, that is not specifically being controlled by the United States Africa Command," he said.

Ward said Africom's main objectives involve building African military capacity and strengthening security cooperation between the United States and African countries. He said that piracy was a criminal matter, and that legal rules have to be followed in pursuing pirates.

"Piracy is a very complex issue. I don't know if you would ever have enough vessels to have coverage of the entire ocean," he said.

There has been some speculation that Islamist rebels who are fighting Somalia's transitional government, and who control much of south and central Somalia, where the tanker has been located, are profiting from the piracy. But the Islamists have condemned the pirates' activities and the radical al-Shabab faction threatened on Friday to combat pirates. Piracy in the region reached a low point when the Islamists were in control of Somalia in 2006.

Ward said that he had no evidence of ties between al-Qaida and Somali pirates, but that the possibility would be a cause for concern.