Friends, relatives and colleagues of an American scientist who went missing during a conference on a Greek island last week said Sunday that search dogs and specialized sea equipment would be used to help locate her.

They said authorities launched the operation on Crete, Greece's largest island and a popular tourist destination, after Suzanne Eaton, 59, a molecular biologist, vanished Tuesday, and described the added search and rescue teams in a statement Sunday on Facebook.

Eaton, a scientist with the Max Planck Institute in Dresden, Germany, disappeared Tuesday near the port of Chania. In a statement, her family said she had been attending a conference at the Orthodox Academy of Crete in the village of Kolymbari, outside Chania.

Colleagues at the conference told authorities they believed she had gone for a run in the area. A public notice of her disappearance has been posted in Greece.

In a statement Friday, the institute said Eaton's running shoes hadn't been found, fueling speculation that she disappeared during a jog. But given Tuesday's intense heat, the statement added, it's also possible she went for a swim.

The institute described Eaton as a leading scientist in her field, as well as a strong athlete, a runner and a senior black belt in taekwondo.

"If anyone can find her way out of a difficult situation, it is Suzanne," the statement said.

The U.S. State Department said Sunday that it was aware of reports of a missing American citizen in Greece. Citing privacy concerns, a spokesperson declined to provide additional details.

Eaton was born in Oakland, California, and earned a doctorate in microbiology from the University of California, Los Angeles, according to the institute.

Police and firefighters, joined by local volunteers, searched an area Friday near Kolymbari.

Emily Kappes, a cousin of the missing scientist, told The Associated Press that Eaton's husband and two sons had traveled to Crete to assist in the search.