New Labor leader Amir Peretz will immediately and simultaneously work on building up his party and negotiating with others on a joint run in the September 17 election, sources close to him told The Jerusalem Post on Wednesday.The sources denied a KAN report that Peretz would first seek to build up Labor and raise it in the polls ahead of negotiations with other parties that must be completed by the August 1 deadline to submit lists of candidates to the Central Elections Committee.“There is no time to lose,” a source close to Peretz said.The sources predicted that Labor would immediately rise in the polls following Peretz’s landslide victory in Tuesday’s primary and his promises that the Sderot resident can take votes away from strongholds of Prime Minister Benjamin Netanyahu’s Likud.Peretz was greeted warmly when he came to Labor’s Tel Aviv headquarters on Wednesday afternoon to make a statement to the press. He revealed to the reporters that he had already spoken in the morning to Blue and White leader Benny Gantz, former prime minister Ehud Barak, new Meretz leader Nitzan Horowitz, Gesher leader Orly Levy-Abecassis and the heads of Shas, United Torah Judaism and Arab parties.“It is still too early to say what parties will run together,” Peretz said.Peretz reiterated his plan to raise Labor from the six seats it won in the April 9 election to 15, by winning votes from former Labor voters returning from other parties, Gesher, Kulanu, Arab and Druze voters and at least four seats from Likud.“I will return Labor from being a mere political party to a political home where all Israelis can feel like they belong,” he said. “We will help Israeli society recover from its internal disputes. At home, there are no enemies, even if there are those who think differently.”Peretz vowed to reach out to MKs Stav Shaffir and Itzik Shmuli, who finished second and third in the primary. The 67-year-old Peretz said that the 34-year-old Shaffir and 39-year-old Shmuli were an integral part of the party’s future.Shaffir told Army Radio on Wednesday morning that she looked forward to working with Peretz but remained upset with Shmuli, who constantly called on her to quit throughout the race. She called Shmuli’s campaign strategy “un-collegial and patronizing.”Following his victory in the Labor race on Tuesday, Benny Gantz announced that he and Peretz were planning on meeting sometime soon.“My blessings to @amirperetz for being elected in the Labor Party primaries,” Gantz said. “I wish him good luck in his position. I spoke to him earlier and we agreed to meet sometime soon.”Former prime minister Ehud Barak tweeted, “Amir, I congratulate you on being elected chairman of the Labor Party and the new path you have set out on. I believe that we can do what is necessary and stand together, together with other forces, in order to bring Israel back on track.”Newly-elected leader of Meretz Nitzan Horowitz said that “we at Meretz are ready to talk about cooperation for the success of the Israeli Left. I expect to speak to Amir in the coming days.”“Congratulation to Amir Peretz on his election as chairman,” Shaffir wrote on Twitter. “I’m thanking members of the Labor Party for trusting me and choosing me for second place. From tomorrow morning we are turning to the real struggle against the Right and replacing Netanyahu’s corrupt government.”Bradley Levin and Stephanie Wasserman contributed to this report.