© REUTERS/ Ivan Alvarado
Laboratory testing confirmed at least 31 cases of infected individuals with the Zika virus who had traveled at risky areas abroad and are now in the United States, and additional 20 cases of infections in US territories, the Centers for Disease Control and Prevention (CDC) announced on Thursday.

"[The] 31 laboratory confirmed travel associated cases" had been found in 11 US states and in Washington DC, the announcement said.

In addition, there are "20 laboratory confirmed cases" of the Zika virus in US Territories, of which 19 in Puerto Rico and one in the US Virgin Islands.

The CDC's announcement comes as the World Health Organization (WHO) International Health Regulations Committee agreed earlier in the day to hold an emergency meeting on the Zika virus on February 1 in Geneva.

The WHO warned earlier in the week that the Zika virus, for which there is no vaccine at present, would likely spread through the Americas if no measures are taken to stop it.

The CDC has warned pregnant women to avoid traveling to at least 24 countries in Latin America, the Caribbean and the Pacific to avoid potential infection. The Zika virus is known to transmit from pregnant women to unborn babies and cause serious birth defects in the brain.