LONDON (Agencies) - US President George W Bush said Monday he understood Afghanistan's anger at attacks by militants based on the border with Pakistan but urged more dialogue between the two neighbours so as to resolve the "testy situation". The US President said the United States could help calm the "testy situation" between Afghanistan and Pakistan, but he refused to endorse Afghanistan President Hamid Karzai's threat to send troops across the border as a means to target terrorists. He called for leaders of Afghanistan and Pakistan to hold talks and share intelligence as both confront Taliban leaders. He also called for more cooperation between Pakistan, Afghanistan and the coalition forces in Afghanistan to tackle the extremists in a forceful way, saying that this would lead to a positive situation in the region. Saying that extremists must not have a safe havens, Bush said his country could help promote better cooperation between the three parties. "We can help calm the situation down and develop a strategy that will prevent these extremists from developing safe haven and having freedom of movement," bush said at a joint news conference with British Prime Minister Gordon Brown after talks with British Prime Minister Gordon Brown. "There can be more dialogue between the Pak (eds: correct) government and the Afghan government," said Bush, who was on a farewell trip to Europe. "There needs to be better cooperation." The US leader stopped short of endorsing Afghan President Hamid Karzai's warning of possible cross-border strikes at militants in Pakistan but said he understood the frustration in Kabul. "It's a testy situation there, and if I'm a president of a country and people are coming from one country to another, allegedly from one country to another, to kill innocent civilians on my side I'd be concerned about it," said Bush. The US leader also called for a new "jirga" to tackle the issue and said this had proved useful in the past, saying: "That'd be a good idea to restart the jirga process." "There's a lot of common ground," he said. "It's in no-one's interest that extremists have a safe haven from which to operate. Obviously, it's a testy situation there." "Our strategy is to deny safe haven to extremists who would do harm to innocent people. And that's the strategy of Afghanistan, it needs to be the strategy of Pakistan. It's in all our interests," he said. British Prime Minister Gordon Brown announced new troops for Afghanistan and tougher sanctions on Iran, delighting visiting Bush. The US President reiterated that "all options" remain on the table against Iran, although stressing he would prefer a diplomatic solution to the West's standoff with Tehran over its suspect nuclear weapons programme. "Now's the time to work together to get it done," Bush said, while adding: "All options are on the table, however." Brown added that Europe was to agree new sanctions against Iran, including freezing assets of the country's biggest bank, after weekend talks by EU foreign policy chief Javier Solana in Tehran. The British prime minister said Britain will freeze assets of Iran's largest bank in a further move to discourage the country from developing nuclear weapons. He said that Britain will work to convince Europe to follow suit. On Afghanistan Brown announced that Britain will send extra troops to the still violence-wracked country, where US, British and other troops are still battling a fierce Taliban insurgency seven years after the country's invasion. On Iran, Brown noted that EU foreign policy chief Javier Solana had had a latest round of talks with Tehran over the weekend. "We await the Iranian response and will do everything possible to maintain the dialogue," he said. "We will take any necessary action so that Iran is aware of the choice it has to make to start to play its part as a full and respected member of the international community or face further isolation." Brown called Bush "a true friend of Britain" and praised his "steadfastness and resoluteness." Bush said of Brown, "He's tough on terror and I appreciate it." Questioned about Iraq, Bush said that history will judge how the US waged the war _ whether more troops should have been deployed and whether they should have been positioned differently. But he said he had no doubts about deposing Iraqi leader Saddam Hussein. "Absolutely it's necessary," the president said.