The U.S. Postal Service is banning international shipments of electronics with lithium batteries such as smartphones, laptops and iPads, citing the risk of fire. Starting May 16, lithium batteries and electronic devices containing lithium batteries will be prohibited from being mailed internationally. They also will not be allowed in shipments to or from Army Post Offices, Fleet Post Offices and Diplomatic Post Offices.

Lithium batteries already are prohibited in mail shipments on international commercial air transportation under International Civil Aviation Organization and Universal Postal Union regulations.

The new regulation will not apply to packages containing lithium batteries or electronic devices mailed within the U.S. on domestic commercial air or ground transportation.

Officials expect that U.S. consumers can resume shipments in most cases after Jan. 1, once the agency develops a new policy "consistent with international standards."

Lithium batteries are believed to have caused at least two fires on cargo planes since 2006.