WASHINGTON - US Special Envoy for Afghanistan and Pakistan Richard Holbrooke, in a telephone call to President Ali Zardari on Thursday, officially conveyed Washington's concern over a peace deal that allows imposition of traditional Islamic law in the Taliban-controlled Swat Valley. Holbrooke said in an interview with CNN that Zardari assured him the pact between the NWFP government and the Tehrik-e-Nifaz-e-Shariat-e-Mohammadi was an 'interim arrangement' to stabilise the restive Swat region. "He (Zardari) does not disagree that the people who are running Swat now are murderous thugs and militants and they pose a danger not only to Pakistan but to the United States," said Holbrooke, who returned to Washington this week after visiting Afghanistan, Pakistan and India as part of his new role coordinating US policy in the region. "It is hard to understand this deal in Swat," he said. "I am concerned, and I know Secretary (Hillary) Clinton is, and the president (Barack Obama) is, that this deal, which is portrayed in the press as a truce, does not turn into a surrender." "I talked to President Zardari of Pakistan on the phone and I expressed to him the same kind of concern you have just stated to me," he told CNN's Wolf Blitzer. Holbrooke said that prevailing in the war in Afghanistan would require countering insurgents in neighbouring Pakistan who operate outside the reach of the Islamabad government. "We've got to deal with Pakistan. We have to stem the deterioration in the tribal areas," he said. Asked about the risk of Pakistan's nuclear arsenal falling into the hands of extremists, Holbrooke said it was 'a legitimate concern'. He said the new US administration had been briefed about the issue by intelligence agencies. "We have been assured by the American intelligence community that this arsenal is under the control of the Pakistan military. But it's an issue of high concern and it can't be ignored." Holbrooke told PBS television earlier that the US was 'troubled and confused' about what happened in Swat, 'because it is not an encouraging trend'. Noting that previous ceasefires have broken down, he said: "And we do not want to see territory ceded to the bad guys, and the people who took over Swat are very bad people." Meanwhile, a State Department spokesman said the US was interested in seeing results of anti-terrorism efforts in Pakistan and will continue to stay in touch with Pakistani officials over this week's Swat peace arrangement. "What we do want to see is results," he said at the daily briefing when asked about how the US Administration was characterizing the peace arrangement. Deputy spokesman Gordon Duguid was asked to elaborate on Ambassador Richard Holbrooke's remarks to PBS channel about the development in Swat in view of past experiences but also added at the same time that it was 'a little too early to come to final conclusions' about the outcome of the peace agreement. In his reply, the spokesman said "what we are is that these types of deals have happened before and (in that context) the direction of events in Swat valley are not in going in a positive way. What we do want to see is results." "We have spoken to the Pakistanis, the ambassador (Holbrooke) has spoken to the Pakistanis. They understand that the threat of terrorism is a threat to them as well as to us. "What we are working towards is a way that we can all address this common problem. That is part of our review, that is part of what we will be talking to the Pakistanis about when the delegation (headed by the Pakistani Foreign Minister) arrives here (next week)," the spokesman added.