US and Philippine warships today conducted a joint patrol of southern waters known as a hunting ground for local Muslim militants. US embassy statement said that US Navy combat ship USS Coronado and the Philippine frigate BRP Ramon Alcaraz carried out their joint patrol of the Sulu Sea. <br/><br/>There is a rising concern over Islamic militancy and piracy in the region. The Abu Sayyaf, an Islamist group based mainly in the southernmost Philippines, have seized hostages from vessels in the Sulu Sea in recent months, sometimes beheading them when ransoms are not paid. <br/><br/><br/>