US State Department officials are warning travelers to exercise “increased caution” amid fears that more terror attacks could slam Sri Lanka.

“Exercise increased caution in Sri Lanka due to terrorism,” an agency advisory issued early Monday morning reads. “Terrorist groups continue plotting possible attacks in Sri Lanka.”

Officials did not name any specific threats.

The warning comes after the South Asian nation was rocked by a series eight explosions at Christian churches and hotels Easter Sunday, killing at least 290 and injuring more than 500 people.

Several US citizens were among the dead, though their identities have not been released.

Sri Lankan officials said the perpetrators were motivated by “religious extremism” but refused to identify what terror group they are believed to belong to. No one has claimed responsibility for the attack.

A total of 24 suspects had been arrested by early Monday morning.