The United States' Department of Homeland Security says it is tightening the rules for citizens re-entering the country from the Caribbean, Mexico or Canada.
It said, effective June 1, it would implement the full requirements of the land and sea phase of Western Hemisphere Travel Initiative (WHTI).
"The proposed rules require most US citizens entering the United States at sea or land ports of entry to have a passport, passport card, or other travel document approved by the Department of Homeland Security."
The Homeland Security Depart-ment said children of US citizens under the age of 16 would be able to present the original or copy of their birth certificate, or other proof of US citizenship, such as a naturalisation certificate or citizenship card.
It said groups of children, ages 16 to 18, when travelling with a school or religious group, social organisation, or sports team, would be able to re-enter under adult supervision with originals or copies of their birth certificates or other proof of citizenship.
Valid id needed
The department said US citizens may present a valid US passport to enter or re-enter the United States when travelling by air, land or sea from Canada, Mexico, the Caribbean region, and Bermuda.
It said the passport card is only valid for re-entry into the United States at land border crossings and sea ports-of-entry from Canada, Mexico, the Caribbean region, and Bermuda.
"As of June 1, the rules are changing when it comes to entering the United States through a land or sea border," the department said.
In the past, US travellers could present a regular driver's license and birth certificate to re-enter the country.
The Homeland Security Department said the new requirements are the final phase of the WHTI, designed to tighten border security in the wake of the September 11, 2001, terrorist attacks on the United States.
"The Western Hemisphere Travel Initiative is a result of the Intelligence Reform and Terrorism Prevention Act of 2004 (IRTPA), requiring all travellers to present a passport or other document that denotes identity and citizenship when entering the United States.
Strengthen security
"The goal of WHTI is to strengthen US border security while facilitating entry for US citizens and legitimate foreign visitors by providing standardized documentation that enables the Department of Homeland Security to quickly and reliably identify a traveller," it added.
The first phase of the WHTI was implemented in 2007, dealing solely with air travel. It required air passengers to have a passport when flying between the United States and Mexico, Canada, the Caribbean or Bermuda.
Caribbean countries had raised concerns about the new rule saying it would lead to a significant decline in the number of American visitors to the region.