By Agence France-Presse
The incident left a seven-year-old boy and an 82-year-old woman dead, according to the mayor's office in Quito, updating an earlier toll of one fatality.
The blast occurred at 11:11 pm on Sunday (0411 GMT Monday) when leaking gas ignited, the mayor's office said.
Authorities added that the victims were dining in the restaurant at the time of the explosion.
It also left about a dozen cars with windshield and body damage, and caused windows to vibrate within two blocks of the area.