New Delhi, July 20 - Describing terrorism and extremism as the 'number one challenge', US Secretary of State Hillary Clinton Monday said she had seen 'real commitment' by Pakistan to fight terrorism and made a pitch for dialogue between New Delhi and Islamabad.

'Combating terrorism and extremism is our number one challenge. It is is something that I take very personally as I was there (in New York) when we were attacked in 2001,' Clinton told nearly 1,000 students who had gathered to listen to her at the Delhi University's convention hall.

'Much of what I have worked in public life in last many years is to avoid another attack on us and anyone else.'

A day after she described Pakistan as the home of a 'global syndicate of terrorism', Clinton reinforced the US' assessment that there is a change in Islamabad's approach towards terrorism.

'We have to look for many ways to support those standing against extremism and I said several times that all through six months we have been in office I have seen a real commitment on the part of the Pakistani government and Pakistani people on taking on extremism that's threatening them and others,' Clinton said.

'It's their hotels being bombed up, their police being killed, their people beheaded and mistreated.

'So anything we can do to try and convey support for those standing against extremism is part of my mission and our country's mission,' she said.

Clinton, who stayed at the Taj Mahal Palace and Tower hotel in Mumbai to express solidarity with 26/11 Mumbai attack victims before coming to New Delhi, stressed that the US had a stake in expanding cooperation with India in the area of counter-terrorism.

'In countries like India who have such a stake to end terrorism and extremism... that has been faced by generation of Indians.