Ibrahima Mamadou Balde petitions for review of a decision of the Board of Immigration Appeals (“BIA”) that refused to reopen Balde’s removal proceedings in response to an untimely motion to reopen filed by Balde. Balde argues that the BIA should have exercised its sua sponte power to reopen the proceedings, pursuant to 8 C.F.R. § 1003.2(a). The BIA’s decision whether to exercise that power, however, is committed to agency discretion by law, and therefore unreviewable. Tamenut v. Mukasey, 521 F.3d 1000, 1005 (8th Cir. 2008) (en banc); see 5 U.S.C. § 701(a)(2). To the extent that Balde contends separately that the BIA “abused its discretion” by denying his untimely motion to reopen, the argument is simply another way of challenging the agency’s refusal to act sua sponte. See Barrie v. Holder, 353 Fed. Appx. 523, 524 (2d Cir. 2009). Accordingly, we deny the petition for review.