JOHANNESBURG — Construction workers have agreed to end a weeklong strike that threatened to derail the completion of already tightly-scheduled projects for the World Cup, union officials and employers said Wednesday.

Workers agreed on a pay increase of 12 percent, below the earlier demand of 13 percent, and work at sites across South Africa is to resume on Thursday.

"The strike is over," said Lesiba Seshoka, spokesman for the National Union of Mineworkers. "We got a good offer."

About 70,000 workers began striking last Wednesday, stopping work on stadiums, airports, freeways and Johannesburg's new high-speed rail link — projects that are scheduled to be finished by December. The World Cup football championship is to be held in the summer of 2010.

Negotiations were concluded in the early hours of Wednesday morning and an agreement was supposed to have been signed at noon (1000 GMT).

Three hours later, though, the agreement still had not been signed. Reporters waiting at the office of the labor mediation body that helped bring about the agreement were not given any reason for the delay.

Dozens of workers in yellow shirts converged at the venue in downtown Johannesburg amid worry that they were not happy with the deal. The workers would not comment, saying they were not permitted to speak to the media.

Seshoka said the deal was still on but that employers were deciding on the final wording of the agreement.

"We have our pens in our hands and are ready to sign," he said.

Danny Jordaan, the head of the World Cup organizing committee, welcomed the end of the dispute. "Let the construction restart in earnest," he said in a statement.

Workers earn a minimum wage of about $300 a month but some casual laborers can take home less than $100 dollars. Unions have also cited increases in fuel and food costs that are making it harder for workers to make ends meet.

The protests drew wide attention. On Tuesday, for intance, at Soccer City, a World Cup finals venue near Soweto, several hundred protesting workers marched around the stadium, brandishing sharpened sticks and singing a Xhosa-language lament about how hard they worked, but how little they made. There have been sporadic reports of violence and intimidation during the strike.

South Africa, a regional economic powerhouse, has an unemployment rate of about 25 percent and has also entered a recession for the first time in nearly two decades. The economy has shrunk 6.4 percent, putting pressure on companies, and there have already been hundreds of layoffs.

The new World Cup wage agreement includes concessions by employers on a number of benefits such as annual leave, bonuses and severance procedures.

Mike Wylie, spokesman for the South African Federation of Civil Engineering Contractors, an employers' group, said management sympathized with workers' concerns.

Wylie, who is also chairman of the WBHO construction company, which had about 10,000 workers go on strike, said the new deal will go a "long way" to improving pay packages. But there was only so far companies can go in boosting wages and benefits, he said.

"It is no good if we are sympathetic and not being sustainable," Wylie said. "If we are not sustainable, a lot of people would lose their jobs."

Wylie said he was confident that builders would make up for a week's worth of lost time. It is important for South Africa to host a successful World Cup and "silence those cynics," he said.

A world-class event would "bring South Africa a lot of credibility and bring investment which would create more jobs in the future."

Associated Press Writer Celean Jacobson and Nkemeleng Nkosi contributed to this report.