Abdullah trying to prove he is no Afghan also-ran

Afghan presidential candidate Abdullah Abdullah is mobbed by supporters as he arrives to give a campaign speech at the Shrine of Hazrat Ali in Mazar-i-Sharif in Balkh province, August 13, 2009.

MAZAR-I-SHARIF, Afghanistan (Reuters) - Afghan President Hamid Karzai's main challenger drew tens of thousands of supporters to an election rally on Thursday, the biggest so far, and warned next week's race would go down to the wire. The huge crowd greeted Abdullah Abdullah, a former foreign minister and regarded as Karzai's strongest rival in the August 20 poll, during a visit to Mazar-i-Sharif, an Abdullah stronghold about 300 kms (190 miles) north of the capital, Kabul.

Karzai needs to win more than 50 percent of the vote to avoid a run-off against the second-placed challenger. A poll earlier this week gave Karzai 45 percent to Abdullah's 25.

"Don't think that this is finished. Don't listen to what others might tell you, this election is very close," Abdullah told supporters at the Shrine of Hazrat Ali, a blue-tiled monument to Islam's fourth caliph, one of the Prophet Mohammad's sons, who is reputedly buried there.

Although half Pashtun, Abdullah draws his support from the country's Tajiks and he was clearly on home turf on Thursday.

The route from the airport to the center of the city was lined by supporters wearing blue caps and T-shirts bearing Abdullah's lightly bearded image. As the convoy reached the shrine, the crowd swelled to around 50,000, and youngsters and the elderly were trampled in the crush.

Later at the governor's mansion, where Karzai's portrait gazed down on dozens of elders and other notables that gathered for a banquet, Abdullah was still clearly the man of the moment.

Security was tight but relaxed, in keeping with a city that has largely escaped the growing Taliban insurgency.

The Taliban, who draw their strength mostly from the Pashtuns of the south and east, have vowed to disrupt the elections and violence is now at the worst levels since the Islamist hardliners were ousted by U.S.-backed Afghan forces in 2001.

Karzai could struggle to get the minimum required to avoid a run-off if violence in Pashtun areas stops people from voting, as many Afghans often vote along ethnic lines.

If the election does go to a run-off, Abdullah is counting on picking up the support of non-Pashtuns.

Abdullah's campaign speech was short on specifics, but he promised to tackle corruption and promote development if elected. Nevertheless, his words went down well with the faithful.

"Before Karzai was popular here but no longer," said Syyed Ali, a campaigner worker for Abdullah.