Kabul - US vice president-elect Joseph Biden travelled to a volatile southern province in his second day in war-shattered Afghanistan on Sunday and met with NATO troops amid increased attacks by Taliban-led insurgents in the region.

Accompanied by US Senator Lindsey Graham, Biden arrived on an unannounced trip to Kabul on Saturday and met with Afghan President Hamid Karzai and General David McKiernan, commander of NATO-led international troops in Afghanistan.

On Sunday Biden made a trip under heavy guard to the volatile province of Kandahar and was briefed on activities of coalition forces in the south by Dutch Major General Mart C de Kruif, the North Atlantic Treaty Organization's regional commander.

"I am very interested in what becomes of this region because it affects us all," Biden told troops in Kandahar, according to a statement issued by the NATO-led force.

Kandahar province, once the stronghold of Taliban leader Mullah Mohammad Omar, has been the centre of the Taliban insurgency since the ouster of their Islamist extremist regime in late 2001. The province along with other neighbouring southern provinces of Helmand, Uruzgan and Zabul witnessed the fiercest battles between Taliban fighters and NATO forces.

The US government has recently announced that it will send up to 30,000 additional troops to Afghanistan this year. Bulk of the additional US soldiers would be stationed in the southern region, where they will reinforce troops from Canada, Britain, the Netherlands and Denmark, which together have more than 13,000 troops in the region.

Biden and NATO commanders at Kandahar airfield, the headquarters of NATO forces in the southern region, discussed the "future of southern Afghanistan, to include the addition of American troops later this year," the alliance said in a statement.

In Kabul Biden discussed the situation in Afghan and the region with President Karzai during their meeting on Saturday evening and assured him of continued and "long-term" support by US government to Afghanistan, according to an Afghan presidential palace statement.

Prior his visit to Afghanistan, Biden went to the Pakistani capital Islamabad, where he met President Asif Ali Zardari and Prime Minister Yousaf Raza Gilani.

Afghanistan and Pakistan are plagued by a Taliban-led insurgency based in the Pashtun-dominated tribal areas straddling their porous shared border. Zardari travelled to Kabul Tuesday for a two-day-trip, where he and Karzai vowed to jointly fight the rebels in their countries.

Biden's visit to Islamabad and Kabul demonstrated the priority of the region for the incoming US administration that is to take office on January 20. President-elect Barack Obama repeatedly said during his election campaign that he would divert the focus of the US's so- called war on terror from Iraq to Afghanistan.

Karzai, who faces reelection towards the end of this year, has been deemed by Obama's team as a weak and ineffective leader, unable to curb widespread corruption in his government. Afghan analysts believe that the new US administration might seek and support a different candidate during the next presidential election slated for fall this year.

In return Karzai lays blame on coalition forces, whose anti- Taliban operations have resulted in the deaths of hundreds of civilians this year alone. Civilians casualties at the hands of international forces have also angered the Afghan public and triggered anti-Western sentiment especially in rural areas of the country.

Biden, whose visit was shrouded in secrecy and did not include any public statements or press conferences, was expected to leave Afghanistan later Sunday.

Though his next destination was not clear, a NATO statement said that he would conclude his tour later this week with stops in Iraq to meet with military officials there. dpa