GENEVA, July 30 (Reuters) - Countries should gradually lift international travel measures based on a thorough risk assessment and must prioritise essential travel for emergencies, the World Health Organization (WHO) said on Thursday (Jul 30).

The WHO recommended that priority should be given to essential travel for emergencies, humanitarian actions, travel of essential personnel, and repatriation.

A surge of new infections in many parts of the world has forced many countries to reimpose some travel restrictions.

The WHO has now urged each country to conduct a risk-benefit analysis of its own and decide on its priorities, before resuming international travel.

In its latest travel advisory, the WHO said countries must take into account the local epidemiology and transmission patterns, the national health and social measures already in place.

Should countries choose to quarantine all travellers on arrival, they must do so after assessing such risks and consider local circumstances, WHO said. There is no "zero risk" when considering the potential importation or exportation of cases in international travel.

Earlier this week, the WHO said that bans on international travel cannot stay in place indefinitely, and countries are going to have to do more to reduce the spread of the novel coronavirus within their borders.

It said last month that it would update its travel guidelines ahead of the northern hemisphere summer holidays.

Earlier in July, it urged travellers to wear masks on planes and keep themselves informed as COVID-19 cases surge again in some countries.

The WHO's previous guidance for travellers has included common-sense advice applicable to other settings such as social distancing, washing your hands and avoiding touching your eyes, nose or mouth.