(Adds Quetta police chief comments, details about teachers)

By Gul Yousufzai and Saad Sayeed

QUETTA/ISLAMABAD, Pakistan May 24 (Reuters) - Armed men kidnapped two Chinese language teachers in the Pakistani city of Quetta on Wednesday, provincial officials said, an attack likely to raise concerns in Beijing about its huge investment plans.

China's ambassador to Pakistan and other officials have urged Islamabad to improve security, especially in the province of Baluchistan, where China is building a new port and funding roads as part of the $57 billion China-Pakistan Economic Corridor that will connect western China with Pakistan's Arabian Sea coast.

"A Chinese couple has been kidnapped, and their personal guard was injured during the incident," Anwar ul Haq Kakar, a spokesman for Baluchistan province, of which Quetta is capital, told Reuters.

Razza Cheema, Quetta police chief, confirmed the attack and said another Chinese woman narrowly evaded the kidnappers outside a language centre in Jinnah, on the outskirts of the city near Quetta's international airport.

"Armed men took the couple into custody at gunpoint when they were coming out from the centre," Cheema told Reuters.

No group has claimed responsibility for the kidnapping, but in the past Islamist militant groups have kidnapped foreigners inside Pakistan for ransom or publicity for their cause.

The number of Pakistani students studying Mandarin has skyrocketed since 2014, when President Xi Jinping signed off on vast plans to fund construction of power and road infrastructure as part of the economic corridor.

It was not immediately clear if the kidnapped Chinese workers were in Pakistan on behalf of the Chinese government or one of the many state-owned enterprises working out of Pakistan.

(Writing by Drazen Jorgic; Editing by Nick Macfie) ((drazen.jorgic@thomsonreuters.com; +92 307 8888 153; Reuters Messaging: drazen.jorgic.thomsonreuters.com@reuters.net))