WASHINGTON: The US has told all its regional partners, including Pakistan, that state support for terrorist proxies will not be tolerated, the Pentagon has said, expressing concern over the free movement of some militant groups in Pakistan that are presenting security challenges for Afghanistan.The Pentagon, in its semi-annual Afghan report to the US Congress that covers the period of June to November 2018, said on Thursday that Taliban and the Haqqani Network retain freedom of movement in Pakistan.The Pentagon's remarks came amidst reports that President Donald Trump is planning to withdraw US troops from Afghanistan.In the report, the Pentagon said that Afghanistan faces a continuing threat from an externally supported insurgency and the highest regional concentration of terrorist groups in the world."In this reporting period, the US continued to call on regional partners to reinforce our messages that state support for terrorist proxies will not be tolerated, that cross-border cooperation between Afghanistan and Pakistan is essential, and that the Taliban cannot achieve its objectives through continued military conflict," the Pentagon said."Although Pakistani military operations have disrupted some militant sanctuaries, certain groups — such as the Taliban and the Haqqani Network — retain freedom of movement in Pakistan. The United States continues to convey to all levels of Pakistani leadership the importance of taking action against all terrorist and militant groups," it said.According to the report, the Haqqani network continues to be an integral part of the Taliban's effort to pressure the Afghan government in Kabul and eastern Afghanistan.Sirajuddin Haqqani's role as a Taliban deputy probably increased Haqqani influence within the Taliban leadership, and resulted in an increase in Haqqani influence to areas outside its normal operating areas of Paktika, Paktiya, and Khost provinces in eastern Afghanistan, it said.The Afghanistan-Pakistan border region remains a sanctuary for various groups, including the Taliban, al-Qaeda core (AQ), al-Qaeda in the Indian Subcontinent (AQIS), the Haqqani Network (HQN), Lashkar-e-Taiba (LeT), Tehrik-e-Taliban Pakistan (TTP), ISIS-K, East Turkestan Islamic Movement (ETIM), and the Islamic Movement of Uzbekistan (IMU).Terrorist sanctuaries on both sides of the border present security challenges for Afghanistan and Pakistan and pose a threat to regional security and stability, the report said.The South Asia Strategy, which was announced by Trump in August 2017, has focused on pressuring Pakistan to limit support and safe-haven for proxy terrorist and militant groups and to play a constructive role in facilitating Afghan reconciliation, the Pentagon said."Regional efforts in the South Asia Strategy aim to expand burden sharing, neutralize potential spoilers to US and coalition efforts, limit threats to the United States and our allies and partners, and develop and support a durable political settlement in Afghanistan," the Pentagon said.The South Asia strategy prioritises regional engagement to limit hedging against the Afghan government and create an international consensus for peace.The Pentagon said the existence of more than 20 terrorist or insurgent groups in Afghanistan and Pakistan requires an Afghan-supported US platform in the region to monitor, contain, and respond to these threats.