MANILA, April 6 (Xinhua) -- A consortium of the Chinese and Filipino firms will build the "new" Marawi, the former main battle area in a five-month war against Islamist militants in the southern Philippines, authorities said on Friday.

Eduardo del Rosario, chairman of the Housing and Urban Development Coordinating Council, said the members of the new Marawi consortium are composed of five Chinese and three local firms and led by China State Construction Engineering Corp. Ltd.

The three local firms are H.S Pow Construction and Development, SDW Realty & Development Inc., and Future homes Philippines, Inc.

Del Rosario said the proposal of the consortium was already selected and negotiation for the terms of reference, costing and project details will start this month.

He added that the Swiss challenge will be undertaken in the first week of May.

A Swiss challenge is a form of public procurement operated in some jurisdictions, which requires a public authority, usually an agency of the government, which has received an unsolicited bid for a public project, or for services to be provided to the government, to publish the bid and invite third parties to match or better it.

He said the Swiss challenge is a hybrid model of public bidding. "But this is faster because we must select initially the one that we will negotiate with the developer," he added.

"We expect the Swiss challenge to be completed by May 25, and if successful again, we will award on May 31 whoever will be the winner in the Swiss challenge," Del Rosario said.

Once awarded on May 31, he said the groundbreaking will be on June 7 of 2018 and completion will be in the last quarter of 2021.

The project includes building village multi-purpose halls, madrasas and health centers, according to Del Rosario.

He said 22 two-storey buildings will be built to replace the destroyed classrooms and facilities.

"We will be constructing a convention center that can accommodate three to five thousand people. A 2-hectare memorial site preserves some facilities as historical sites and port facilities," Del Rosario said.

Extremists and terrorists attacked Marawi City in May last year, triggering five-month heavy fighting that ruined a big part of the city. At least 1,200 people were killed in the war to retake the city and thousands of its residents were also displaced.