PARIS , France ( CNN ) -- Hundreds of French workers , angry about proposed layoffs at a Caterpillar factory , were holding executives of the company hostage Tuesday , a spokesman for the workers said . Caterpillar 's French staff say they are angry about a lack of negotiations over layoffs . It is at least the third time this month that French workers threatened with cutbacks have blockaded managers in their offices to demand negotiations . Executives were released unharmed in both previous situations . The latest incident started Tuesday morning at the office of the construction equipment company in the southeastern city of Grenoble . The workers were angry that Caterpillar had proposed cutting more than 700 jobs and would not negotiate , said Nicolas Benoit , a spokesman for the workers ' union . They did not want to harm the Caterpillar executives , Benoit told CNN . One hostage was released Tuesday evening leaving workers with four captives inside the Caterpillar building . The released man was a human resources director identified only as Mr. Petit , because he has heart problems , union representative Bernard Patrick told CNN . Petit had a heart attack a few weeks ago , Patrick said . The four others still being held are Nicolas Polutnik , the head of operations ; two other executives ; and Petit 's personal assistant , he said . About 500 employees were also outside the building protesting . A top Caterpillar executive called the hostage-taking unhelpful . `` The actions that are taking place today , led by a small minority of individuals , are not helping as we work for a positive resolution of this situation , '' said Chris Schena , Caterpillar vice president with responsibility for manufacturing operations in Europe , Africa and the Middle East , in a statement . `` The best way to resolve this matter is to continue the negotiations through the Works Council to find a solution that 's fair to our employees and allows Caterpillar to remain a leader in a rapidly changing global marketplace , '' Schena said , adding that the company was `` concerned for the safety of our employees . '' Benoit said all the workers wanted to do was negotiate with Caterpillar and they were upset that the company did not show up to two earlier scheduled negotiating sessions . The employees being held in their office were being allowed to get food , Benoit added . Police arrived at the scene two hours after the incident began but it had not been settled . Employees at a French 3M factory held a manager hostage for more than 24 hours Wednesday and Thursday of last week over a dispute about terms for laid-off staff . Luc Rousselet , who was unharmed , was allowed to leave the plant in Pithiviers , central France , early on Thursday morning after talks between unions and officials from 3M France . Earlier this month , the boss of Sony France was held overnight before workers freed him after he agreed to reopen talks on compensation when the factory closed . France has been hit by nationwide strikes twice in the past two months .
NEW : Workers release one of five people being held hostage at Caterpillar factory . Workers angry that Caterpillar propose cutting more than 700 jobs . They did not want to harm the executives but get them to negotiate , official says . A senior Caterpillar executive called the hostage-taking `` unhelpful ''