New Delhi: The United States on Friday ordered all families of American diplomats posted in Sri Lanka to leave the country saying there is a possibility of further terror attacks. It also raised its travel warning to “Level 3”, advising civilians to reconsider going there.

In a travel advisory issued following the serial terrorist bombings, the US State Department also permitted the voluntary departure of non-emergency government employees of the American mission and their families.

The UK and Australia had also advised their citizens not to travel to Sri Lanka unless their journey is essential as terrorists were "likely" to carry out further attacks in the country, following the deadly Easter Sunday bombings that killed 253 people and injured over 500.

According to advisories, future attacks could be indiscriminate, including in places visited by foreigners.

In the immediate aftermath of the bombings, the The UK Foreign Office (FCO) updated its guidance, urging British citizens in the country to avoid large gatherings.

Foreign Office officials told those at the briefing that the change to travel advice was not due to fresh intelligence but instead a necessary precaution.

The situation still remains volatile in Sri Lanka after nine suicide bombers, believed to be members of a local Islamist extremist group called National Thowheed Jamath (NTJ), carried out the blasts that killed 253 people and wounded more than 500 others.

The death toll from the Islamist attack on Easter Sunday was revised downwards.