Fear surrounding the eruption of Mount Agung in Bali escalated after nearby Mount Sinabung, in Northern Sumatra, suddenly exploded on Wednesday.
Shocking Twitter footage shows the volcano spewing ash 2.5km into the air.
Thick smoke then surrounds the volcano, expanding outwards because of the wind.
Thousands of locals were forced to flee from the area and warned to stay at least 7km away in case of further eruptions.
The sudden explosion sparked additional fears over a possible eruption of Mount Agung in Bali which has been under close monitoring for days.
There have been more than 650 instances of seismic activity recorded each day since last Thursday, September 21. On some days there have been almost 1,000 tremors.
The number of people forced to flee their homes near Mount Agung has now topped 144,000, according to Indonesia’s National Disaster Management Authority (BNPB).
A statement from Pak Kasbani, head of Indonesia’s geological agency, said volcanic earthquakes continue to be felt in high numbers with increased magnitude, “indicating brittle failure inside the volcano caused by magma movement."
White steam clouds have been observed rising between 50m and 200m above the summit.
Bali authorities have claimed that tourism has not been affected by the possibility of a volcanic eruption and have urged holidaymakers to still come to the island.
The island’s tourism chief AA Gede Yuniartha Putra said: "Bali tourism is safe. Do not spread the misleading news that Bali is not safe because Mount Agung is on the highest alert status. Please, come and visit Bali.”
But the Australian and UK Government have advised residents of Bali and travellers that ash clouds from the erupting volcano could significantly impact the island.