Riyadh: Saudi authorities have arrested 10 more suspects in an alleged Iranian spy ring unveiled two months ago, an interior ministry spokesman said on Tuesday.

The eight Saudis, a Lebanese and a Turk bring the number of people arrested to 28, the official SPA news agency quoted the spokesman as saying.

A Lebanese arrested in March has since been released.

“The results of investigations by security services have led to the arrest of the other 10 involved in spying for this cell,” the spokesman said.

On March 19, the interior ministry said authorities had arrested 16 Saudis, an Iranian and a Lebanese in four regions including the oil-rich Eastern Province, where Saudi Arabia’s Shiite community is concentrated.

Iran has denied any involvement in the alleged spy ring.

Saudi Arabia’s rulers have strained ties with Iran, which deteriorated further after a Saudi-led military intervention quelled pro-democracy protests in neighbouring Bahrain in early 2011.

Earlier this month, Kuwait’s cassation court upheld a life sentence against four people for their role in a pro-Iran espionage network, and agreed to free another three members of the ring.

The four were originally sentenced to death by a lower court, but the court of appeals had converted the decision to life in prison for the four defendants.

However, the public prosecutor had called for a tougher sentence against the seven members of the cell, four Iranians, one Kuwaiti, one Syrian and one Dominican.