Australia is reviewing its telecommunications sector after Optus failed to connect 624 emergency calls last week, linked to four deaths.

The outage affected calls to “0-0-0,” Australia’s emergency number.

Optus CEO Stephen Rue apologized, citing lapses in established processes.

Communications Minister Anika Wells said the industry watchdog is investigating, and there will be consequences for Optus and other telecoms.

Optus and Telstra have previously faced fines for emergency call failures, ABC News has reported.

Prime Minister Anthony Albanese called Optus’ actions “completely unacceptable” and suggested a possible leadership change.