Two opposition candidates agreed Sunday to broaden their joint policy manifesto to security and economic issues and accelerate negotiations to merge their candidacy.

Independent candidate Ahn Cheol-soo made the proposal while announcing his key campaign pledges. Later in the day his Democratic United Party counterpart Moon Jae-in accepted the suggestion.

The agreement was reached as representatives of the two campaigns neared a conclusion in their ongoing talks on political reform, the foremost precondition attached by Ahn for their alliance.

The two sides are expected to announce the political statement early this week, campaign officials said.

The six-member task force for political reform held a fourth round of talks Sunday.

“We have settled on a considerable range of issues. We will meet Monday again to discuss further remaining differences and write the draft statement simultaneously,” a member of the team told reporters after the meeting.

Sources said the two camps may launch three working-level task forces as early as Monday in charge of drafting joint declarations on national security and economic democratic as well as negotiate detailed methods for merging their campaigns.

Talks for their union is likely to gain speed as Ahn wrapped up his campaign pledges Sunday. He previously said he would come to table on candidacy merger only after he finalizes his own manifesto and the two sides strike an agreement on political reform.

“The key agenda for the next president are economy, national security and political reform. By suggesting joint visions on these three issues, candidate Moon and I will be able to display the philosophy and blueprint of the next government,” Ahn said while briefing on his election pledges.

Park Sun-sook, co-chief of Ahn’s campaign headquarters, explained that political reform remains his top priority, but the two sides cannot afford to wait for the result of the coordination on the issue.

The negotiations are expected to be a tough tug-of-war as Ahn is believed to want the choice made through an opinion poll while Moon favors a mix of an opinion poll, an open primary and delegate vote.

Moon and Ahn agreed last week to pick a single candidate by Nov. 25-26, the candidate registration period for the Dec. 19 presidential election.

Though they reached a consensus on their general political philosophy, they are still at odds over details including Ahn’s proposals to sharply reduce the number of lawmakers and abolish the central party system.

On Sunday, Ahn further demanded the three candidates including Park Geun-hye of the ruling Saenuri Party cut their campaign expenses to half the government-set ceiling, which stands at 56 billion won ($51.5 million)

“In order to achieve political reform, the election process should be free from the power of money and organizations,” he said.

DUP officials said the party agrees in principle to his new proposal. “We hope it will be realized through active consultations,” Moon’s spokesman Jin Sung-joon said.

The Saenuri Party stepped up the offensives against the upcoming Moon-Ahn union.

“It is no more than a collusion to have Moon elected as president and Ahn become prime minister,” said Lee Jung-hyun, Park’s public communications chief.

By Bae Hyun-jung (tellme@heraldcorp.com)