New Delhi, Sep 18 - Ahead of the meeting between foreign ministers of India and Pakistan in New York this month, the US Friday intensified pressure on Islamabad to ensure 'swift and lengthy' punishment for six Mumbai terror attack suspects, including 26/11 mastermind Hafiz Saeed.

US Ambassador to India Timothy J. Roemer met Prime Minister Manmohan Singh and discussed the agenda for his state visit to Washington in November, the first by a foreign leader during the Obama administration.

Roemer conveyed US President Barack Obama's warm greetings and anticipation at seeing the prime minister in Pittsburgh for the G20 meeting and for the prime minister's official state visit in November, said the US embassy in a statement.

'The upcoming official state visit, the first by a foreign leader during the Obama administration, is a testament to the vital importance of the US-India strategic partnership in addressing our greatest global challenges,' Roemer stressed.

Earlier in the day, Roemer met Home Minister P. Chidambaram and discussed issues relating to strengthening counter-terror cooperation between India and the US.

'Swift and lengthy punishment for six suspects of Mumbai attacks in Pakistan is important for the US and India,' Roemer told reporters after meeting Chidambaram.

The ambassador said it was important for the US, India and the world that Pakistan takes action against Saeed, the founder of Lashkar-e-Taiba-turned Jamaat-ud-Dawa and dismantle the terror infrastructure in that country, a demand India has been making for long but without much response from the Pakistani side.

'Going after Hafiz Saeed and dismantling terror infrastructure in that region is extremely important for both US and India,' the envoy said.