Fighters from the Islamic State group have attacked an oil field in Libya and nine foreign workers are unaccounted for, officials said Saturday.

Austrian Foreign Ministry spokesman Martin Weiss said several security personnel were killed in Friday afternoon’s attack at the site in al-Ghani, south of Sirte.

Security teams retook the site, but nine foreign workers are unaccounted for, including one Austrian, one Czech and the seven others, who are non-EU citizens, Weiss said.

No demands have been made by any group or individual for their return.

The Czech Foreign Ministry also confirmed that a Czech national was missing after the attack. Ministry spokeswoman Michaela Lagronova said the ministry is contact with the family of the missing person and is cooperating with Austria.

This is an Associated Press story.