"We want it made known to us who pays for political advertisements... who are these persons or organizations, so that we can count and understand if it's not being funded with money of unclear origin," Straume told Latvian Radio.
After the meeting, which lasted only an hour, Straume said that Facebook is open to cooperation, and a video conference is planned in May with both parties to keep contact and discuss further cooperation.
While KNAB recently floated the idea of outright blocking Facebook prior to the Saeima elections, slated for October 2018, Straume said that the question is not on the agenda anymore.
Straume and Facebook reps reportedly discussed ensuring transparency in the upcoming parliamentary elections, as well as preventing the spread of fake news and misinformation.
Other social networks, noted Straume, are not as responsive to cooperation, while the Latvian social network Draugiem.lv will not be running political ads at all.
Last week Latvia's president Raimonds Vējonis met Facebook representatives at the Facebook headquarters in the Silicon Valley during his visit to the US.
"We agreed that there'll be a specific person on the side of Facebook, who'll be responsible and who we'll be able to contact if we see any problems, so that we can find common solutions in overcoming challenges," Vējonis said after the meeting.
Facebook is very much in the eye of the public after reports of data leaks erupted with the Cambridge Analytica reportedly mining data of tens of millions of Facebook users and using them to manipulate the US presidential election. As reported by LSM, Cambridge Analytica have been active in Latvia too.