DELHI (Reuters) - A Chinese navy ship supported by an Indian navy helicopter thwarted an attack by suspected Somali pirates on a Tuvalu-flagged merchant ship, India’s defense ministry said on Sunday.

The ship, known as OS 35, was reported to be under attack on Saturday.

The Indian defense ministry said four of its navy ships in the vicinity responded to a distress signal from the ship and reached the bulk carrier early on Sunday.

It said the crew had taken refuge in the ship’s strong room, know as the citadel, once they learnt they were under attack in line with established safe shipping operating procedures.

“An Indian Navy helicopter undertook aerial reconnaissance of the merchant vessel at night, and at sunrise ... (to) ascertain the location of pirates, if still on board,” the defense ministry said in a statement.

“Subsequently ... a boarding party from the nearby Chinese Navy ship went on board the merchant ship, while the Indian Naval helicopter provided air cover for the operation.”

China’s defense ministry said in a statement a Chinese navy frigate on patrol in the area responded to the distress call from the ship, which it said had been hijacked by pirates. A helicopter conducted surveillance of the ship before 16 navy special forces soldiers were sent aboard to rescue the sailors.

It did not mention the Indian involvement.

The Indian defense ministry said all the 19 Filipino crew of the ship were safe and the captain of the ship thanked the Indian navy for their response and for providing air cover.

John Steed of aid group Oceans Beyond Piracy told Reuters the ship was sailing under navy escort to its next port.

The United Kingdom Maritime Trade Operations, which coordinates shipping in the Gulf of Aden area, said on its website the pirates had used a skiff to approach the vessel.

The attempted hijacking comes days after pirates seized an Indian dhow that was on route to Bossaso from Dubai.

Experts said some ship owners were becoming lax after a long period of calm, and that some were using a route known as the Socotra Gap, between Somalia and Socotra Island, to save time and cost regardless of the piracy risks.

At their peak in 2011, pirates launched 237 attacks off the coast of Somalia, according to the International Maritime Bureau, and took hundreds of hostages.

Their actions cost the world economy $7 billion and earned the pirates some $160 million in ransoms, according to the bureau.

China’s defense ministry said Chinese navy ships had helped patrol the Gulf of Aden and Somali waters since 2008, responding to several pirate attacks and conducting a small number of rescues.