Facebook Wednesday took issue with Google and Verizon's proposal to exempt cellular networks from rules that would ensure equal treatment of Internet traffic, saying the social-networking giant supports equal treatment on "both landline and wireless networks."

The comments from Facebook are the latest criticisms leveled at the Google-Verizon proposal from the technology world. Soon after the companies announced the plan on Monday, some consumer advocates derided the proposal because of its two big exemptions: mobile networks...