A junior AfD association Junge Alternative (JA) and Der Fluegel union are marked as "suspects" in BfV documents, which means that, unlike "test case" people and entities, they can be put under surveillance, according to Tagesspiegel outlet.
BfV President Thomas Haldenwang is expected to make a speech on the issue later in the day.
German Foreign Minister Heiko Maas, who belongs to the Social Democratic Party, commented on the reports by saying that "those who discriminate against people because of their ancestry, are acting in a racist and nationalist manner."
"Some components of the AfD are a case for the [Office for the] Protection of the Constitution. However, the problem is not solved with surveillance. Above all, we have to handle AfD objectively and politically", Maas said on Twitter.
Maas suggested back in 2016, when he served as the justice minister, that the right-wing party merited being put under the domestic intelligence surveillance.
Last year, the regional BfV office in the German state of Thuringia marked the local AfD association for future investigation.