As a result of a brewing feud between American and Afghan officials over peace talks with the Taliban, a senior United States diplomat has reportedly told President Ashraf Ghani that Washington will no longer deal with his national security adviser. The decision for the US not to speak with Hamdullah Mohib is likely to raise tensions between Washington and Kabul at a time when the Afghan government is already uneasy at the White House push to agree on a settlement with the Taliban to end the 18-year-old conflict. Negotiations have mainly focused on a pull out of American troops and how the Taliban can ensure it will stop militant groups using Afghanistan as a base to plan and carry out attacks against the United States. Kabul has not been involved in the talks, leading to tensions. Mr Mohib launched a blistering public attack last Thursday on the chief US negotiator, Special Representative Zalmay Khalilzad, saying he was seeking personal benefit by side-lining the government. In a conversation with journalists in the US last week, he said that the US-Taliban talks were increasing the militant group’s legitimacy at the expense of the government’s and suggested Mr Khalizad, an American-Afghan national, was seeking to become to create "a caretaker government of which he would then become viceroy." Viceroy was the title of the colonial administrator of British-ruled India. The following day, US Undersecretary of State for Political Affairs David Hale told Mr Ghani by phone that Mr Mohib would no longer be received in Washington and US civilian and military officials would not do business with him, the sources said. "Hale called Ghani and told him that Mohib is no longer welcome in DC. The US will not deal with him in Kabul or in DC any more," said a former senior Afghan official, who like the other sources requested anonymity because of the issue's sensitivity. Kabul fears that Washington is intent on finalising a US troop pullout to fulfil a vow by President Donald Trump, undermining its ability to reach a political pact with the Taliban that preserves gains, such as women's education, won since the 2001 US invasion ended the militants' harsh version of Islamic rule. The former Afghan official said he saw the move as an effort to compel Mr Ghani to "oust" Mr Mohib, who became the president's national security adviser after serving as his envoy to Washington. A second source, a US congressional aide, agreed that pressuring Mr Ghani to end contacts with Mr Mohib was "one way of looking at this" because the State Department provides funding for the Afghan president's national security council staff. The State Department and Afghan embassy in the US declined or were unavailable for comment. The Afghan government's exclusion from the US-Taliban talks in Qatar has been a source of some concern in Kabul. The Taliban has long refused to sit down with the government, saying they were a puppet of the US who were the real power brokers. The State Department responded with a strong statement quoting Mr Hale as telling Mr Mohib later on Thursday that his comments "only serve to hinder the bilateral relationship and the peace process." The latest round of peace talks ended on March 11 after 16 days. The sides reported progress, but no accord on the withdrawal of US-led international forces and the Taliban's counter-extremist assurances. US negotiators also are pressing the insurgents to accept a ceasefire and talks with Afghan society representatives, including government officials. In an interview on Monday, Afghanistan's ambassador to Qatar, Faizullah Kakar, said that another country should not be negotiating on the use of Afghan territory by militants. "It is the government that should be deciding, whoever the government is, that the territory is used or not used against another country," he said.