LOME - Togo's main opposition leader Gilchrist Olympio returned from exile on Saturday and said nothing short of victory in next month's presidential elections would be acceptable.

"If we don't win these elections, we will know that once again there has been massive fraud in the country and that the system hasn't changed," said Olympio, who came to Togo's capital Lome from neighboring Ghana on Saturday morning.

"If the results are rigged again, this time the real fight will begin," he told reporters before heading to a stadium where more than 10,000 opposition supporters had gathered.

Togo's long-standing leader Gnassingbe Eyadema died on Feb. 5 after 38 years of firm rule and his son, Faure Gnassingbe, was named the country's new leader by the army that day in violation of the constitution.

The move sparked international outrage and violent protests in the capital of the former French colony. After coming under huge international pressure, Gnassingbe agreed to step aside and run in elections due on April 24.

The main opposition parties have named one candidate, Emmanuel Bob-Akitani, the vice-president of Olympio's Union of Forces for Change party who came second with 34.1 percent of the vote in 2003 elections.

Olympio, the son of Togo's first post-independence president who was killed in a coup, fled the country in 1992 after an assassination attempt. He cannot stand in the Apri poll because he has not been resident for the 12 months prior to the vote.

Thousands of opposition supporters dressed in yellow took to the streets to welcome Olympio's convoy of nine vehicles after it crossed the border and snaked its way slowly to his father's house near the U.S. embassy.

Dressed in a traditional robe, Olympio told a news conference the opposition would reject a Gnassingbe win.

"We would mobilize the people and the region, we would mobilize the international community so that the results are rejected and we can hold the vote again," he said.

Olympio is expected to return to Ghana this evening and come back to Togo periodically in the coming weeks to help the opposition election campaign.