The NHTSA says it is opening an investigation after the agency identified concerns due to crash events after vehicles had the recall software update installed
Zuckerberg, who is visiting India to participate in an event to boost Internet usage, did not give details.
Facebook's final WhatsApp acquisition price tag has risen an additional $3 billion to roughly $22 billion because of the increased value of Facebook's stock in recent months.
WhatsApp works across different types of phones, across borders, and without advertising.
The app only charges a 99 cent annual subscription fee, which is waived for the first year.