UPDATE (1200 GMT): The official news agency of the SSPX, DICI, has now confirmed the following:
Bishop Williamson, as he declared in his interview [to Der Spiegel] does not wish to "hurt in any way the work of the Fraternity"; that is why he accepted, on January 31, the decision of the Superior General [Bishop Fellay] to relieve him of his position as director of the Seminary of La Reja (Argentina). [In French: DICI - permanent link]
[Original post:] In an e-mail message sent to the most prestigious Argentinian daily, La Nación (Monday edition), the superior for the South American District of the Priestly Fraternity of Saint Pius X (FSSPX / SSPX), Father Christian Bouchacourt, confirmed that Bishop Richard Williamson "was removed from his charge as head of the seminary" of Nuestra Señora Corredentora of La Reja (Province of Buenos Aires, Argentina).
The name of Williamson's successor as director of the seminary was not mentioned by Bouchacourt, though rumors indicate that it could be Bishop Alfonso de Galarreta, a Spaniard raised in Argentina, currently living in Madrid.
Related: Der Spiegel interviews Bishop Williamson (in English), including a comment with which all reasonable observers will agree: "Apparently Germany's leftist Catholicism has not yet forgiven Ratzinger for becoming pope."