More explosions have been heard across the Gulf states, and at least three people have been killed in the United Arab Emirates as Iran carries out attacks in retaliation for strikes by the United States and Israel that killed its supreme leader, Ayatollah Ali Khamenei, and other top officials.

The explosions were heard for a second day on Sunday in Dubai, the UAE; Bahrain’s capital, Manama; and Qatar’s capital, Doha, raising fears of a wider conflict in a region long seen as a haven of peace and security in an otherwise turbulent Middle East.

Witnesses in Doha reported hearing several loud bangs and seeing thick, black smoke rising on the clear morning horizon in the south of the city

Shortly afterwards, another wave of explosions reverberated through Dubai, a regional business hub. Puffs of white smoke from missile interceptions were seen in the city’s skies while billows of dark smoke rose over Jebel Ali, one of the busiest ports in the Middle East.

The three people killed in the UAE attacks were Pakistani, Nepalese and Bangladeshi nationals, the Ministry of Defence in Abu Dhabi said.

Explosions were also reported in Manama with witnesses reporting at least four loud explosions. There was no immediate report of any damage or injuries from Sunday’s blasts.