Manish Chand/IANS

Washington, Apr 11: India\'s Prime Minister Manmohan Singh arrived here Sunday on a four-day visit to attend the 42-nation Nuclear Security Summit that will focus on non-proliferation and nuclear terrorism.

A string of bilateral meetings between Manmohan Singh and the leaders of the US, France and Canada have also been planned on the sidelines of the summit.

Manmohan Singh was warmly welcomed at Andrews Air Force base by White House chief of protocol Capricia Marshall. India's ambassador to the US Meera Shankar was also present at the airport.

In their first bilateral meeting since the state dinner in Washington in November last year, Manmohan Singh is expected to raise with Obama the extradition of David Coleman Headley, a key plotter of 26/11 attacks, to India when the two meet here Sunday.

The issue will be discussed in detail when National Security Adviser Shivshankar Menon meets his counterpart Gen (Retd) James Jones.

"We will keep pushing...This will be one of the issues...We'll use every occasion to seek access (to Headley)," sources said.

As their meeting takes place a day ahead of the Nuclear Security Summit, the two leaders are set to discuss issues relating to evolving global nuclear architecture and nuclear terrorism that is expected to be the focus of the summit.