Khar told the upper house of parliament late Tuesday that Afghan refugees living in Pakistan were responsible. "We are not responsible if Afghan refugees crossed the border and entered Kabul, stayed in a guest house and attacked Professor Rabbani," officials quoted Khar as telling the Senate. A senior Pakistani official told AFP that the presence of Afghan refugees was "an important issue for Pakistan" and "a problem for Afghanistan". "We don't want to forcibly expel them. We are trying to resolve this issue in a negotiated manner because more than 90 percent of terrorist attacks in Pakistan trace back to Afghan refugees."