Egyptian presidential finalists both claimed on Monday their lead in the run-off voting, the results of which will be officially announced by the presidential electoral commission on Thursday.

Ahmed Abdul-Atii, a campaigner of the Muslim Brotherhood, told reporters its candidate Mohamed Morsi won the election with 52 percent of the votes based on 97 percent of all polling stations. The press briefing was held by the Brotherhood at around 4 a.m. ( 0200 GMT) Monday, just six hours after the two-day voting process ended at 10 p.m. (2000 GMT) on Sunday.

However, the campaign team of Morsi's rival, ex-premier Ahmed Shafiq, rejected Morsi's claim as completely untrue. The counting process of the capital Cairo was completed on Monday evening.

"Shafiq is leading by 250,000 votes now after the exclusion of invalid ballots," said spokesman Ahmed Sarhan of Shafiq's campaign team on Monday evening. He indicated Shafiq's votes may still increase.

"We call on Egyptian people to wait for the official announcement of the results before prematurely jumping to any conclusions," Sarhan was quoted by official MENA news agency as saying. "The final results will be totally different from what Morsi's campaign team announced."

Morsi's campaign team added many invalid votes, he pointed out. Sarhan also said "the Supreme Presidential Election Commission said it has nothing to do with any results announced by Morsi's campaign, especially as the counting process is still ongoing in several governorates."

General coordinator of Shafiq's campaign Mohamed Aboul Makarem said on Monday afternoon Shafiq has got from 51 percent to 52 percent of the total votes.

"We don't know why Morsi's campaign behaved like that and considered themselves winner before the vote counting is finished, " he told Xinhua by telephone.

The Muslim Brotherhood's website said Morsi was leading the race with 52 percent of the total votes, while Shafiq got 48 percent.

Earlier on Monday, a senior member of Shafiq's campaign told Xinhua anonymously that they disagreed with Brotherhood's claim of victory.

"The counting is still going on now in Cairo and other big governorates. It's impossible to finish all counting in such a short time, so we doubt the results of the Muslim Brotherhood. There is some exaggeration."

Morsi's supporters flocked early Monday morning into Tahrir Square to celebrate his victory. "Get the remnants away. Morsi's renaissance program is our way out," the supporters shouted.

"I'm so happy that we get rid of the former regime's remnant Shafiq and I hope everyone welcomes the results," Osama Ahmed, a 40-year-old supporter of Morsi, told Xinhua.

The April 6 youth movement expressed congratulations to Morsi's campaign on the initial results, urging Morsi to keep his promises of unifying political forces and achieving the revolution goals.

Spokesperson for Salafists' Nour Party said Morsi's win is a victory for the entire Egypt.

Morsi showed up at the early Monday's press conference and delivered impassioned thanks to his supporters, calling for solidarity among Egyptian voters.

"To those who were killed and injured during the revolution, I solute to their families. Egypt will not forget them. I respect their rights," Morsi said.

He continued to say he would not take revenge towards anybody in the future. "All the Egyptians are my brothers and friends, I assure all Copts, churches, Al-Azhar Mosque that I will lead Egypt to a civil, secular and democratic state," said Morsi, adding that all citizens were equal.

"We should not look behind. We have to work hard for a better Egypt where nobody oppresses another," he added.

Complicated political row

Just as the voting ended and counting began on Sunday night, the Supreme Council of the Armed Forces (SCAF), which took over power in February 2011 after Mubarak's resignation, issued a supplementary constitutional declaration. The amendments stipulated the powers of the military.

According to the declaration published on the official Ahram newspaper on Monday, the SCAF members are in charge of deciding on all issues related to the armed forces, including the appointment of its leaders and extension of their office terms. The current head of the SCAF is to act the commander-in-chief of the armed forces and minister of defense until a new constitution is drafted.

The president can only declare war after the approval of the SCAF. The SCAF will assume legislative powers after the dissolution of the parliament.

The supplementary constitutional declaration came after the Supreme Constitutional Court dissolved the Islamist-dominated People's Assembly (lower house of parliament) due to its unconstitutionality.

But the Brotherhood's Freedom and Justice Party (FJP) rejected both the dissolution of parliament and the supplementary declaration.

In a statement on Monday, the FJP said "the issuance of a complementary constitutional declaration is completely unacceptable because this is on longer within SCAF's powers."

The party vowed to join all popular events against the constitutional declaration and dissolution of parliament. Political powers called for a mass protest on Tuesday against the SCAF.

The SCAF said in a press conference Monday that they will deliver the power to the elected president by the end of this month.

"We will deliver the power by the end of June to the elected president in a great celebration which will be witnessed by the whole world," said Mohamed al-Assar, a member of the SCAF.

After Mubarak was forced to resign after 18 days of mass protests against his 29-year rule in February last year, Egypt's constitution was suspended and parliament dissolved.

From last November to February, Egyptians elected two houses of the parliament, which saw Islamist parties winning more than 70 percent of the seats in both chambers.