A Chinese worker and his ­driver were wounded in ­Pakistan on Monday in a bomb attack that appears linked to ethnic ­nationalists opposed to plans for extensive Chinese ­investment, police said.

The attack is likely to ­heighten concerns about the China-Pakistan economic corridor (CPEC), involving $46 billion in Chinese investment in roads, power plants, railway lines and a new port on the ­Arabian Sea.

Pakistan, which is ­battling ­Islamist militants and ­separatist guerrillas in parts of the ­country, has promised to ensure the security of the ­project.

The Chinese man and his Pakistani driver were slightly wounded in the attack in the southern province of Sindh, said provincial police chief Allah Dino Khawaja.

"Apparently, the attack was aimed at the Chinese national," Khawaja said.

The low-intensity bomb went off by the roadside in a suburb of Karachi, Pakistan's largest city, shattering the windows of the van in which the men were traveling.

A pamphlet signed by a group called the Sindhudesh Revolutionary Army, an ethnic Sindhi separatist group, was found at the site, police said.

According to a photograph of the material seen by Reuters, the pamphlet said China wants to "attack Sindh and enslave its people."

The group's statement is thought to refer to the CPEC, which was announced last year, though it is unclear whether the Chinese national was working on a CPEC project.

CPEC is part of China's Belt and Road initiative, which aims to ease the transport of Chinese exports to foreign markets.