SANAA, March 31 -- For almost half a century, Chinese doctors and nurses have been trying to save lives in Yemen, where locals call them "white angels" for their expertise.0 Zhang Xinfeng, who led a team of nine medical professionals in the southern city of Taiz which has seen conflicts since earlier this month and airstrikes for almost a week, said the director of their hospital intended to persuade them to stay in the city, but finally escorted Zhang's convoy to al-Hodayda port after he realized that there was no way to protect the Chinese at the moment.

Before the evacuation, there were about 620 Chinese living in Yemen, including a team of 58 medical staff providing aid in Yemen and hundreds of Chinese working there in such industries as oil drilling, road and bridge construction, telecommunications and fishery.

In the past two days, 571 of them were evacuated from al-Hodayda port and Aden port by two Chinese navy frigates to Djibouti where they will take flights back to China.

The Chinese government places great importance to the safety of Chinese nationals and interests in Yemen, and it has wasted no time in withdrawing these nationals since the security situation there abruptly deteriorated on Thursday, Foreign Ministry spokeswoman Hua Chunying told a daily press briefing.

While packing bags, Wang Yueyang, an intern, found five bullets that he picked up at the yard this month. "Last week when I was watering the cabbage in the yard, a bullet hit the ground just one or two meters away," he said.

"I received a message from Chinese doctors in Sanaa that records sound of explosions in September last year when I was receiving training in China for working abroad, which made me really scared," he said. "But we choose to come to the country as others did in the past 49 years."

After clashes broke out in Sanaa in January between President Abd-Rabbu Mansour Hadi's forces and Shiite Houthi militants, electricity was reduced to about five hours each day in the block where the Sanaa medical team lives.

Li Jiasheng, who led the team of 11 doctors and nurses including Wang, said that everyone has to live in darkness after running out fuel since they did not have enough diesel for generators.

"It was our first time to see airstrikes, rather than in the movies, in the wee hours on March 26 when we were sleeping," Li said.

"I felt that I was rolled off the bed as if an earthquake was hitting the house and the sound of anti-aircraft artillery which was deployed on the hill near our house was much more louder than fireworks," he added.

"The city was lit up by explosions and artillery fire. We stayed in the basement for the whole night, and received phone calls from our Yemeni colleagues in the morning who suggested we return to China, like our families did," Li said.

Since 1966, the Chinese government has sent more than 3,500 medical staff to Yemen as part of its aid to the impoverished country. More than 10 million patients have been treated and some 600,000 operations carried out by the Chinese medical staff since then.

Several Chinese doctors who died in Yemen were buried uphill in a graveyard that overlooks the capital city to which they dedicated their lives.