KARACHI: Militants trying to disrupt construction of an "economic corridor" linking China with Pakistan's coast have killed 44 workers since 2014, an official said on Thursday, a rising toll likely to reinforce Chinese worry about the project's security.

The China-Pakistan Economic Corridor (CPEC) is a $46 billion network of roads, railways and energy pipelines linking western China to a deep-water port on Pakistan's Arabian Sea coast, which passes through Pakistan's troubled Baluchistan province.

Pakistani officials say they have taken tough measures and that security has greatly improved in Baluchistan, a resource-rich region where ethnic Baluch separatists have battled the government for years. They oppose the CPEC.

Colonel Zafar Iqbal, a spokesman for construction company Frontier Works Organisation (FWO), said all of the workers killed were Pakistani and most fell victim to roadside bombs and attacks on construction sites.

"The latest figure has climbed up to 44 deaths and over 100 wounded men on CPEC projects mainly road construction in Baluchistan, which began in 2014," Iqbal told Reuters.

In November 2015, the official figure was 25 killed, indicating that the toll has accelerated this year.

The Pakistani projects are part of a Chinese plan to build land, sea and air routes across Asia and beyond boosting trade and winning new markets overseas for Chinese companies as domestic growth slows.

Chinese officials have appealed for improved security in Baluchistan and other regions where projects are planned or under way.

In a bid to address their fears, Pakistan last year created an army division, believed to number more than 10,000 troops, to focus specifically on protecting CPEC projects and Chinese workers.

FWO, which is owned by the Pakistani army, has been awarded the bulk of road-building contracts in Baluchistan and other volatile areas in Pakistan.

Pakistani officials concede security problems remain in Baluchistan, but say the work is progressing ahead of schedule.

About $4.5 billion of the planned investment in the corridor will go towards road infrastructure, with two-thirds of the total $46 billion investment funnelled towards energy projects.

Officials expect the CPEC projects to significantly boost Pakistan's economic growth above the current 5 percent a year.

Overall security in Pakistan has improved over the past few years but Islamist groups, especially those linked to the Pakistani Taliban, still stage major attacks from time to time.

Last month, Islamists killed 74 people in a hospital bombing in the city of Quetta, the provincial capital of Baluchistan.