ISLAMABAD (AP) — Shaken by multiple recent militant attacks, Pakistani authorities have locked down the capital in a major security move before senior officials from several nations arrive for an Asian security group meeting.

A three-day holiday started Monday in normally bustling Islamabad and the nearby garrison city of Rawalpindi, and Pakistan has deployed troops and blocked key roads, making it difficult even for ambulances to take patients to hospitals. Some doctors on blocked roads asked police to remove barricades so that they could go to hospitals, but police instead asked them and others to take longer routes.

The main event of the Shanghai Cooperation Organization will be held Wednesday when leaders and officials from the member states gather to discuss how to boost their security cooperation and economic ties.

In years past, ordinary Pakistanis used to line up on both sides of the main roads to welcome any dignitaries visiting the country, but authorities say they had to take harsh security measures because of the fears of militant attacks.

Officials say their priority is to peacefully hold the meeting of the Asian security grouping that was established in 2001 by China and Russia to discuss security concerns in Central Asia and the wider region. Other members of the SCO are Iran, India, Pakistan, Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan.

Militants in recent weeks killed dozens of people in multiple attacks in restive northwest and southwestern bordering Afghanistan. But, security experts say militants have limited capacity to strike in Islamabad.

However, two Chinese engineers were also killed on Oct. 6 in a suicide bombing outside the country’s largest airport in Karachi, the capital of southern Sindh province. The attack was claimed by a separatist group.

The slain engineers were working on a power project under the China-Pakistan Economic Corridor or CPEC, which includes building and improving roads and rail systems to link western China’s Xinjiang region to Pakistan’s southwestern Gwadar port on the Arabian sea.

Despite the killing of two Chinese, China's Premier Li Qiang arrived in the capital on Monday to attend the SCO meeting. Li on Monday virtually inaugurated a Beijing-funded airport built in restive southwestern Balochistan where separatists have warned China to wind up CPEC-related projects to avoid any further attacks on the Chinese engineers working in Pakistan.

However, Pakistan’s military has responded to the threat from the outlawed Baloch Liberation Army by launching multiple raids on their hideouts, and vowed to eliminate them in Balochistan and elsewhere in the country.