|Last month's arrests were the largest of alleged operatives in many years [Reuters]
Al-Qaeda members planned to kill Saudi Arabian government and security officials, as well as media workers, by sending poisoned gifts to their offices, a Saudi interior ministry official was quoted as telling the Reuters news agency.
Last month, Saudi Arabia said it had captured 149 al-Qaeda-linked fighters over the past few months. They were accused of raising money and recruiting members to carry out attacks inside the kingdom.
The group "planned to rob banks and companies to finance their operations", the official, who declined to be named, said on Saturday.
"Using poisoned perfume ... is one of the ways the arrested people planned to carry out their assassinations," he said.
The operatives, who have apparently revealed this information to Saudi security forces since their arrest, belonged to 19 al-Qaeda cells and included 124 Saudis and 25 foreigners.
'Change in tactics'
"Changes from explosives to chemicals is significant because it demonstrates resolve and the ability to try to trick the security services," Theodore Karasik, a security analyst at the Dubai-based group INEGMA, said.
"This is a change in tactics. It means they are trying every possible way to spread chaos ... The security services are very lucky that they discovered this," he said.
The arrests announced last month were part of one of the largest crackdowns on al-Qaeda by Saudi Arabia in years.
The groups detained have links to fighters in Somalia and Yemen, the interior ministry said.
Saudi Arabia has been fighting al-Qaeda for years but in 2009 the Saudi wing of the group merged the Yemeni group to form Al-Qaeda in the Arabian Peninsula (AQAP), based in Yemen.
In August 2009, a suicide bomber posing as a repentant al-Qaeda fighter tried to assassinate Saudi Arabia's senior anti-terrorism official, Prince Mohammed bin Nayef, but inflicted only minor injuries.
In October, a plot to send two parcel bombs from Yemen to the US was foiled after a tip off from Saudi Arabia.
In March, the kingdom arrested 113 al-Qaeda figures, including alleged suicide bombers who it said had been planning attacks on energy facilities in the world's top oil-exporting country.