The US government has approved the sale of six Boeing AH-64E Apache and six Bell AH-1Z Viper attack helicopters to Manila.

The sale package is not finalised, as it is subject to customer acceptance, the US Defense Security Cooperation Agency (DSCA) said on 30 April. The Philippines plans to choose one of the two models.

The possible sale of the AH-64Es and related equipment is estimated to cost $1.5 billion, while the AH-1Zs and related equipment are pegged at $450 million, according to the DSCA.

“The proposed sale will assist the Philippines in developing and maintaining strong self-defence, counter-terrorism and critical infrastructure protection capabilities,” the agency says. “The Philippines will have no difficulty absorbing this equipment and support into its armed forces.”

Both packages contain additional equipment and weapons, such as GE Aviation turboshaft engines, GPS, radar warning receivers, BAE Systems Advanced Precision Kill Weapon Systems (APKWS) guided rockets and Lockheed Martin AGM-114 Hellfire II air-to-surface missiles. Each package also contains spares and support equipment, such as repair parts and training devices.

However, the AH-64E sales package has a much more extensive list of add-ons and weapons. For instance, the AH-1Z package includes 26 examples of the APKWS rocket, while the Apache offering includes 300. The larger quantity of weapons and related equipment offered in the Boeing package partly accounts for its higher price.

The Philippines is an important ally of the USA in the eastern Pacific Ocean. The country sits between Taiwan and the South China Sea – two areas claimed by China. The USA contests Beijing’s claims.

The Philippines also has struggled with Muslim separatists in its southern islands. Some separatists have affiliated themselves with international Islamic terrorist groups such as the Islamic State of Iraq and Syria.

Modern attack helicopters would help the Philippines armed forces deal with either threat.