Two women wearing protective masks walk outside Beijing railway station in Beijing on January 22, 2020.

The U.S. State Department raised its travel advisory for China from Level 3 to Level 4, citing the coronavirus outbreak in that country.

"Do not travel to China due to novel coronavirus first identified in Wuhan, China," the department said in its notice about the Level 4 advisory.

"Those currently in China should consider departing using commercial means," it said in an online statement.

The new warning comes after the WHO on Thursday declared the outbreak a global health emergency. That rare designation helps the international agency mobilize financial and political support to contain the outbreak.

On Thursday, the U.S. Centers for Disease Control and Prevention also confirmed the nation's first human-to-human transmission of the virus. Illinois health officials said in a CDC press briefing that the new patient is the spouse of a Chicago woman who brought the infection back from Wuhan, China, the epicenter of the outbreak.

On Friday morning Beijing time, China's National Health Commission said the virus has killed 213 people as the number of cases rose to 9,692.

The State Department only flags a handful of countries as Level 4, its highest level "due to greater likelihood of life-threatening risks." Around the time of its new designation for China, the State Department had already marked the following as Level 4:

Iraq

Iran

Mali

Central African Republic

Venezuela

Yemen

South Sudan

Burkina Faso

Syria

Somalia

Afghanistan

North Korea

Libya

To see the latest updates on the coronavirus outbreak, visit CNBC's live blog.﻿

— CNBC's Weizhen Tan, Berkeley Lovelace Jr. and William Feuer contributed to this report.