Greece's coast guard says it's conducting a search-and-rescue operation after a speedboat and a tourist vessel collided off the island of Aegina, leaving at least three people dead and three others injured.

The coast guard said Tuesday there were believed to have been about 15-20 people onboard the tourist boat, which was transporting people from Aegina in the Saronic Gulf near Athens to a beach on the nearby deserted islet of Moni. It was unclear how many people were on the speedboat.

The agency said a number of people were rescued and it was focusing on finding survivors. It did not have the exact number of rescued or know yet how the accident occurred.

Aegina's proximity to the Greek capital makes it a popular destination for Greeks and foreign tourists, AP reports.