MOSUL, Iraq, May 10 (UPI) -- The Iraqi Army, supported by nearly 10,000 Sunni tribesmen, has initiated a major operation against al-Qaida in the Iraqi city of Mosul, the BBC said.

The British broadcaster said the military -- with assistance of area tribesmen loyal to the Iraqi government -- had begun searching for al-Qaida leaders in Mosul as part of Operation Lion's Roar.

The city in northern Iraq has long been seen as the last stronghold for al-Qaida operatives in Iraq and a military operation in the city had been expected, the BBC said.

Iraqi Prime Minister Nouri al-Maliki has said al-Qaida has been gradually weakening in Iraq to the point it could soon be removed from Iraq altogether.

The BBC said the new military operation was initiated following reports that al-Qaida leader Abu Ayyub al-Masri was arrested in Mosul. U.S. officials denied the al-Qaida official had been arrested.

BEIRUT, Lebanon, May 10 (UPI) -- Hezbollah gunmen holding portions of western Beirut will all be withdrawn from the Lebanese capital, the militant group said Saturday.

The announcement followed a statement by the Lebanese Army, which said it would work to resolve the dispute that brought violence to Beirut during the past four days, The New York Times reported.

Army officials had proposed that an investigation into the private telephone network used by Hezbollah could resolve the issue. The network was initially challenged by government officials, but military officials said they could adequately review it without affecting the militant group's security.

In addition, army officials proposed that the current chief of airport security in Beirut, Gen. Wafiq Choucair, should be retained in his post. Choucair is known for his ties with the militant group, the Times said.

Choucair's position had been threatened by government officials, who alleged a spy camera was found on an airport road.

The Times said this week's street battle in Lebanon have left at least 29 people dead.

KHARTOUM, Sudan, May 10 (UPI) -- The Sudanese government claimed Saturday that an attempt by Darfur rebels to seize the capital of Khartoum had been put down.

An unnamed U.S. source in the area told The Washington Post that rebels had joined a government faction attempting a coup.

The Justice and Equality Movement, usually known by its initials, JEM, said it was in control of Omdurman, a town across the river from Khartoum, and was using it as a base to oust the government of President Omar Bashir.

The international community has failed to protect our people, and now we are in a position to do it, said Eltahir Elfaki, a JEM leader currently in exile in Libya. We are not going to stop until this regime is removed once and for all.

The U.S. source told the Post that several military officers were arrested late Friday and that the rebels, uncharacteristically, appeared to have heavy artillery.

JOHANNESBURG, South Africa, May 10 (UPI) -- Opposition leader Morgan Tsvangirai said Saturday he plans to return to Zimbabwe to take part in a presidential runoff election.

Tsvangirai's supporters have been the target of recent political violence in Zimbabwe. He said the election should be supervised by an electoral commission to ensure the will of the people is heard, The Washington Post said Saturday.

We will contest the runoff, and the people will finally prevail, Tsvangirai said in Pretoria, South Africa. The people have spoken before, and the people will speak again. I am ready, and the people are ready for the final round.

The Movement for Democratic Change opposition group claims that Tsvangirai defeated President Robert Mugabe in the March 29 election by an outright majority. The group said that majority meant a second round of elections would be unnecessary.

However, the electoral commission said the opposition leader did not win by a large enough percentage, making a runoff election a necessity, the Post reported.