WASHINGTON (AFP) - US special forces have stepped up counterterrorism missions against some of the most lethal groups in Afghanistan and plan an even bigger expansion next year, The New York Times reported late Saturday. Citing unnamed US military commanders, the newspaper said the commandos from the Armys Delta Force and the Navys classified Seals units have had success weakening the network of Sirajuddin Haqqani, the strongest Taliban fighter in eastern Afghanistan. Haqqanis group has used its bases in neighbouring Pakistan to carry out deadly strikes in and around Kabul, the Afghan capital, according to the report. Guided by intercepted cellphone communications, the US commandos have also killed some important Taliban operatives in Marja, a Taliban stronghold in Helmand Province in the south, the paper noted. Marine commanders say they believe there are some 1,000 fighters holed up in the town, according to the report. Although US President Barack Obama and his aides have not publicly discussed these highly classified missions as part of the administrations new strategy for Afghanistan and Pakistan, the counter-terrorism operations are expected to increase along with the deployment of 30,000 more US troops next year. Monitoring Desk adds: The commandos are the same elite forces that have been pursuing Osama bin Laden, captured Saddam Hussein in Iraq in 2003 and led the hunt that ended in 2006 in the death of Abu Musab al-Zarqawi, the leader in Iraq of the insurgent group Al Qaeda in Mesopotamia. In recent interviews here, commanders explained that the special-mission units from the Joint Special Operations Command were playing a pivotal role in hurting some of the toughest groups, and buying some time before American reinforcements arrived and more Afghan security forces could be trained. They are extremely effective in the areas where we are focused, said one US Gen in Afghanistan about the commandos, speaking on the condition of anonymity because of the classified status of the missions.