Australia has been asked by the US to join the air operation against Islamic State targets in Syria, reports on Friday said. The formal request for increased involvement by the RAAF, including the potential for Australian airstrikes, was sent to the Australian embassy in Washington DC on Thursday, the Australian reports. The paper says "the request primarily seeks to allow Australian planes to cross the border in support of coalition operations and so improve the ability to chase Islamic State terror fighters who flee Iraq". The paper says there are no requests for ground forces. Liberal MP Dan Tehan, the head of parliament's intelligence and security committee, last week called on Australia to expand its operations in Iraq to Syria. Christopher Pyne, the education minister and leader of the house, told the Nine network "I don't believe any decision has been made by the government and obviously we would be briefing the opposition", adding a briefing was scheduled for early next week about "any developments that might occur there". Pyne said Australian aircraft were already refuelling coalition fighter jets carrying out bombing missions in Syria. "And we would do everything on a very strong legal basis if we were to take that further action," he said. Tanya Plibersek, deputy Labor leader, said she had no details of the request. "There was a briefing scheduled for this week. That was cancelled so we don't know what is being asked of us at the moment," she told the Nine network. Asked if Australia should be dropping aid to victims of the conflict, rather than bombs, Plibersek said it wasn't a case of one or the other. "These are the people being raped, murdered, sold into slavery, chased from their homes – of course we should be doing more. "It's not either or. We do need to have a strong military response to this organisation [Isis] that doesn't exempt us from also helping the victims of the organisation." Treasurer Joe Hockey said there were processes for dealing with such requests. But he noted Australia's Isis "enemies" see no borders in the Middle East. "We have an obligation to do whatever we can to stop the evil that they are perpetrating," he told reporters in Canberra.