Italian navymen yesterday arrested nine Somali pirates who were trying to seize a Liberian-owned merchant ship in the Gulf of Aden, a naval press spokesman said.

"Today, around 0600 GMT, our Maestrale frigate received a distress call from a merchant ship, the Maria K, that had been attacked by a pirate boat, while it was less than 20 kilometres away" from the Italian vessel, he said.

The spokesman said the ship's helicopter fired several warning shots before the Maestrale arrived on the scene to make the arrests.

According to Ansa news agency, prosecutors in Rome will question the pirates via videolink from the Maestrale in the next few days.

The Maria K is registered in the Caribbean island of St Vincent and the Grenadines.

The arrests come as Italy gears up to host a meeting on June 10 to address the roots of Somalia's piracy crisis.

According to the International Maritime Bureau, pirate attacks off the Horn of Africa country, in the first quarter of this year surged tenfold to 61, compared with the same period in 2008, when six attacks occurred.

A total of 114 attempted attacks have occurred since the start of the year, and pirates have seized 29 ships.