Saudi Arabia plans to raise its arms purchases from the United States to $90 billion from the $60 billion announced last year, as the kingdom seeks to upgrade it navy, diplomats in the Gulf said this week.

Last year, US officials said Riyadh planned to buy $60 billion worth of military aircraft, including upgrades to existing fleets.   

Saudi Arabia, the world's largest oil producer, is boosting its defences as it faces off with Iran for influence in the Gulf Arab region.

'There is a plan for Saudi to spend an extra $30 billion to upgrade its navy fleet,' said a Western diplomat in the Gulf. 'This extra amount also includes maintenance and training for the forces,' another Gulf-based diplomat said.   

A Saudi government adviser said he expected the deal to upgrade the navy fleet would be completed soon.   

'The chances this deal won't be finalised are very remote. The money will basically be used to update the eastern fleet,' he said, adding the upgrade was part of a separate programme to the $60 billion plan announced last year.   

US officials said last year the $60 billion programme would be complete in 15 to 20 years. It was not clear over how many years the $30 billion addition would last.   

'Saudi Arabia is getting more aggressive in its foreign policy and is trying to match that by increasing its arms to meet the increasing challenges that it's faced with today,' said Theodore Karasik, a Dubai-based military analyst.

'These challenges range from what's going to happen next in Yemen to the increased risk of piracy in its waters -- that's why they are trying to boost their land and navy fleets.'  - Reuters