Pakistan's capital was under strict security lockdown as Premier Li Qiang landed in the city on Monday ahead of a heads-of-government gathering of the Shanghai Cooperation Organisation (SCO) this week.

Li's visit is the first by a Chinese premier to Pakistan in 11 years, Pakistan's Prime Minister's Office said.

Pakistan's Prime Minister Shehbaz Sharif received Li at the airport.

The government has announced a three-day public holiday in Islamabad, with schools and businesses shut and large contingents of police and paramilitary forces deployed.

Pakistan army troops will be responsible for the security of the capital's Red Zone, the location of the parliament and a diplomatic enclave and where most of the meetings will take place, according to the interior ministry.

The threat alert has been high in the South Asian nation ahead of the SCO summit, especially after the killing of two Chinese engineers and shooting to death of 21 miners.

Tensions have mounted after jailed former Prime Minister Imran Khan called for a protest on October 15 to press for his release and agitate against the coalition government, following violent clashes between his party loyalists and security forces.

Islamabad has sought to curb all movement of Chinese nationals in the city, citing fears they could be targets for violence from separatist militants.

The 23rd meeting of the SCO, which comprises nine full members including China, India, Iran and Russia, is scheduled for Tuesday and Wednesday in Islamabad.

As well as attending the SCO summit, Li is also undertaking a four-day bilateral visit to Pakistan from Monday to Thursday, accompanied by senior officials, Pakistan's foreign office said.

Li and Pakistani Prime Minister Shehbaz Sharif will lead their respective delegations to discuss economic and trade ties and cooperation under the China Pakistan Economic Corridor (CPEC), a US$65 billion investment in the South Asian country under the Belt and Road Initiative.

Li will also inaugurate the CPEC funded Gwadar International Airport in restive southwestern Balochistan province, which borders Afghanistan and Iran, Pakistan's prime minister's office said.

In addition to Li, the SCO participants will be represented by the prime ministers of Russia, Belarus, Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan as well as the first vice president of Iran and external affairs minister of India. (Reuters)