This story was written by CBS News' Sami Yousafzai in Islamabad and CBSNews.com's Tucker Reals in London.
A Taliban commander in southern Afghanistan tells CBS News the Islamic fundamentalist movement that once ruled the country is ready to defend their traditional heartland from a pending U.S. and NATO military offensive, and hundreds of militants are pouring in from neighboring Pakistan to help.
"Hundreds of Taliban (foot soldiers) and bombers are ready for the assault around Kandahar and we challenge the U.S. and NATO to this forthcoming operation," Muhammad Khalil, a commander in the southeastern province told CBS News in a telephone interview from the region.
Khalil claimed "hundreds of Pakistani militants" from the lawless tribal areas along the two nations' shared border have arrived in Kandahar, the Taliban's homeland, and were prepared to battle the Western and Afghan forces over the summer.
Fighting has already begun as elite American troops fan out in the mud-hut villages surrounding the provincial capital, Kandahar city, ahead of the expected offensive planned around a huge influx of about 30,000 additional American troops ordered by President Obama.
Khalil said his men were responsible for an attack Tuesday night on an Afghan security company just a mile from the main U.S. base in the region. He said three suicide bombers and a group of gunmen laid siege to the compound near the regional airport, which the U.S. forces are using as their base, for about two hours.
Above: Afghans inspect the site of a bombing attack near Kandahar city, Afghanistan, April 28, 2010.
A spokesman for the governor of Kandahar, Zalmay Ayubi, tells CBS News the attack began when a suicide bomber walked to the gate of the private security company and blew himself up. After the first bomber, rockets and grenades were lobed at the base. At least three other suicide bombers stormed the base and started firing, then blowing themselves up during the firefight.
Ayubi tells CBS four guards were killed, 30 more injured, and more than 20 vehicles were burned in the attack. He says two militants were arrested and four bombers were killed.
The influx of new fighters to Kandahar is part of the Taliban's attempt to avoid a military defeat in their heartland along the lines of what happened in neighboring Helmand province just a couple months ago.
That operation, a smaller-scale precursor to the Kandahar fight, saw Western and Afghan troops force the militants out of the strategic town of Marjah. Despite a slower than expected effort to rebuild the area and see the Afghan authorities' power take root, it remains largely secure, thanks in no small part to a continuing U.S. Marine presence.
Kandahar promises to be a much bloodier fight, for the Americans and their allies, and the Taliban. The city is home to hundreds of thousands of Afghans, many of whom sympathize with the Taliban movement.
U.S. military leaders have warned the American public to brace for increasing casualty figures as the operation ramps up in Kandahar.