Somali pirates have stepped up the seizure of ships along the coast of the lawless country. A Greek-owned vessel with 22 crew members was hijacked early Tuesday and there is word that a Togo-flagged vessel has also been seized. Monday, two Egyptian fishing vessels were hijacked, in a sign that the attacks will continue despite rescue missions by American and French forces over the weekend.

Early Tuesday pirates seized the MV Irene, a Greek-flagged ship carrying 22 crew members. A U.S. Navy spokesman told the AP news agency the crew is from the Philippines.

The ship was passing through the Gulf of Aden on its way from Jordan to India when it was hijacked in a rare nighttime attack, facilitated by the light from a nearly full moon. NATO officials say a Togo-flagged ship, the MV Sea Horse has also been taken over.

A day earlier, pirates captured two Egyptian fishing boats carrying as many as 24 sailors, according to Egypt's Foreign Ministry.

The attacks suggest that the latest wave of piracy in the area is not slowing, despite the fact that five pirates were killed over the weekend when American and French special forces freed hostages in separate operations.

Pirates have vowed to continue their attacks, and there are fears that the operations may have antagonized pirates. Jama Si'ad, a pirate in the coastal town of Harardhere, a hub of pirate activity, said that pirates would retaliate against American citizens.

He said in the future, pirates would execute French and American crew members that they capture and would display their bodies to the media.

Whether such threats are more than just rhetoric remains to be seen. But on Monday, U.S. president Barack Obama said the American government is committed to combating the rise in piracy, and the U.S. military is considering options for escalating its response.  However, U.S. Defense Secretary Robert Gates noted the difficulty of the job, saying Monday that economic improvements within Somalia will ultimately be needed to stop the attacks.

For the past few months, as many as 20 warships from various countries have been patrolling the waters off the Somali coast in an attempt to deter pirate attacks. But the area is huge, and while the frequency of hijackings appeared to drop off earlier this year, the recent spate of attacks has dispelled any hopes that the threat has receded.

According to the International Maritime Bureau, more than a dozen ships, and more than 200 hostages are currently being held by Somali pirates, seeking ransom payments.

While the United States and France have quickly mobilized military operations when their citizens have been hijacked, other hostages, many of them from the Philippines and other poorer countries, have had to wait for ransom negotiations to unfold. Many have been held captive for several months.

The World Food Program also said Tuesday that piracy is threatening the delivery of food aid to war-torn Somalia, 90 percent of which arrives by sea.