Washington/Nairobi  - Richard Phillips, the American captain dramatically rescued from pirates on Sunday, arrived in the Kenyan port of Mombasa Thursday aboard a US Navy destroyer escorting a second US freighter attacked by pirates.

Phillips is captain of the Maersk Alabama, whose crew repelled an attempted pirate hijacking. The captain was held hostage for five days on a lifeboat.

He was freed Sunday when five US Navy snipers killed the three pirates holding him.

Phillips had been due to arrive in Mombasa on Wednesday, but the ship carrying him, the USS Bainbridge, had to divert to help the Liberty Sun, a US-flagged cargo ship carrying food aid when it was attacked on Tuesday.

Pirates fired rocket-propelled grenades and automatic weapons at the Liberty Sun, which sustained damage but managed to steam away from the attack.

The Liberty Sun arrived in Mombasa a few hours before the Bainbridge.

Phillips was expected to fly home later Thursday on a charter flight. His crew flew back to the US on Wednesday.

Pirate activity has picked up in recent weeks after a lull due to bad weather.

Over 20 ships have been attacked in the last three weeks. Nine of those ships are in pirate hands, bringing the total number of ships being held to 16. Around 250 crew members are being held hostage.

In 2008, pirates seized more than 40 vessels in and around the Gulf of Aden and collected tens of millions of dollars in ransoms, prompting the international community to send warships to the region.

Around 15 warships from the European Union, a US-led coalition task force and individual countries such as Russia, India and China patrol an area of about 2.85 million square kilometres.

The presence of the warships has appeared to have had little effect, and observers say that only by tackling insecurity and poverty in Somalia will piracy finally be halted.

Somalia has been without a functioning government since the 1991 ouster of dictator Mohamed Siad Barre.

US Secretary of State Hillary Rodham Clinton on Wednesday announced a four-point plan to counter piracy, including steps to improve security, policing and governance in Somalia.(dpa)