The United States asked Pakistan to act against perpetrators of Mumbai attacks, including Jamaat-ud Dawa chief Hafiz Saeed, saying it wants to see results. Describing Lashkar-e-Taiba as a global threat, US Ambassador to India Timothy J Roemer said Pakistan should recognise the dangers and dismantle the terror infrastructure existing on its soil.<br/><br/>Addressing media persons in New Delhi ahead of the Prime Minister Dr. Manmohan Singh's visit to Washington from Tuesday Mr. Roemer said, situation in Pakistan, the Mumbai attacks and cooperation in counter-terrorism will be high on the agenda when Dr. Singh meets the US President Barrack Obama.<br/>