RIYADH (AFP) - Iran's foreign minister arrived in Saudi Arabia on Saturday for a rare visit to the regional rival to offer condolences after the death of King Abdullah, television pictures showed.

Saudi officials greeted Foreign Minister Mohammad Javad Zarif after he arrived at a military airport in the capital Riyadh.

Iran and Saudi, seen as the region's foremost Shi'ite and Sunni Muslim powers, have had troubled relations in recent years after taking different sides in the Syrian civil war.

Teheran has backed Syrian President Bashar al-Assad while Riyadh supported Sunni rebels trying to topple him. Zarif has previously declined a Saudi invitation to visit the kingdom, citing continued negotiations between his country and international powers over Iran's disputed nuclear programme.

In August last year Iran's Deputy Foreign Minister Hossein Amir-Abdollahian held talks with Saudi Foreign Minister Prince Saud al-Faisal in the Red Sea city of Jeddah. That was the first high-level Iranian visit to the kingdom since Hassan Rouhani became the Islamic republic's president a year earlier. They discussed the fight against Islamic State in Iraq and Syria (ISIS), who both nations oppose.

Rouhani has stated his wish to improve relations with Iran's neighbours, especially Saudi Arabia. Since the June 2013 election of Rouhani, regarded as a moderate, Iran has engaged in a diplomatic push with Riyadh but relations have soured in recent months over the falling global price of oil.

Both countries are members of the Organisation of the Petroleum Exporting Countries (Opec) but Iranian officials have expressed frustration at Saudi Arabia for not taking steps to cut supply. Iran has been among the oil exporting countries worst hit by the price fall.

Rouhani expressed his condolences after the death on Friday of King Abdullah, who has been succeeded by his half-brother Salman.