KABUL, Afghanistan (AP) --
Biden and South Carolina Republican Sen. Lindsey Graham met with U.S. Gen. David McKiernan, head of the NATO-led force in Afghanistan, said Col. Greg Julian, a U.S. military spokesman. Later, the visiting senators will meet with President Hamid Karzai.
"Gen. McKiernan explained the current situation and talked about the incoming troops and the need for additional enablers ... things like helicopters, engineers, military police, transportation assets," Julian said.
"As we expand in the south we will need those additional enablers to cover for the troops," he said.
The U.S. is rushing up to 30,000 American troops over to Afghanistan, some of whom will go to its volatile southern provinces, to combat a Taliban insurgency that has sent violence to record levels.
In 2008, 151 American troops died in the country, more than in any other year since the 2001 U.S.-led invasion to oust the Taliban.
President-elect Barack Obama campaigned on a platform of ending the war in Iraq and refocusing American military efforts on the conflict in Afghanistan.
Obama has called Afghanistan an "urgent crisis," saying it's time to heed the call from U.S. commanders for significantly more U.S. troops. Biden's visit is a clear signal that Obama's new administration plans to make the region an immediate priority.
Biden discussed priorities in Afghanistan for 2009 with the United Nations' top representative for the country, Kai Eide, U.N. spokesman Adrian Edwards said.
"Their meeting touched on security, political and developmental issues, including donor coordination, police reform and regional cooperation," Edwards said.
The senator also thanked some of the U.S. troops stationed at NATO's Kabul headquarters.
"Thank you, I mean it sincerely," Biden told the troops, according to a NATO statement. "It's a big, big deal, what you're doing here. You're making a big sacrifice in a (challenging) environment. Thank you for your service." The senator from Delaware will take office as vice president on Jan. 20.
There are some 32,000 U.S. troops in Afghanistan serving alongside another 32,000 other NATO-led and coalition troops, the highest number since the ouster of the Taliban from power.
Southern Afghanistan has now become the center of the Taliban-led insurgency in Afghanistan, with daily attacks, roadside bombings and suicide attacks targeting foreign and Afghan troops, which has left some 6,400 people - mostly militants - dead in 2008 alone.
Biden's visit to Afghanistan follows his trip to neighboring Pakistan, where aides said he met with President Asif Ali Zadari, Prime Minister Yousuf Raza Gilani and Foreign Minister Shah Mehmood Qureshi.
Biden and Graham also discussed counter-terrorism, counterinsurgency and the economy with Pakistan's interior adviser Rehman Malik and army chief Gen. Ashfaq Kayani.
Afghanistan and Pakistan are embroiled in a vicious Taliban-led insurgency, which has claimed thousands of lives.
Biden's tour comes after five U.S. soldiers were killed in two separate attacks in southern Afghanistan, and as U.S. officials warned the violence would likely intensify in the coming year.
Three U.S. soldiers were killed in an explosion Friday in southern Afghanistan, Julian said. Another two soldiers were killed in a suicide attack Thursday in a marketplace in Kandahar province's Maywand district.