New Delhi, Apr 8 (IANS): In a potential game-changer in volatile bilateral ties, Prime Minister Manmohan Singh Sunday accepted an invitation to visit Pakistan, with India indicating that concrete actions against anti-India terrorists and a speedier resolution of less contentious issues like disputes over the Siachen glacier and Sir Creek marshland could form the showpiece of the much-awaited trip.

India and Pakistan, which resumed their dialogue in February last year after a post 26/11 pause, moved a step closer to their "common desire" of normalising relations after a businesslike lunch and 40 minutes one-one-talks talks between visiting Pakistan President Asif Ali Zardari and Manmohan Singh here.

Zardari touched down here in the morning on a six-hour private visit cloaked as a pilgrimage to the Sufi shrine at Ajmer in Rajasthan.

Manmohan Singh pressed Pakistan to bring the perpetrators of the Mumbai terror spree to justice and act against 26/11 mastermind Hafiz Saeed, who is continuing with his hate India speeches with impunity, but the talks largely focused on mapping out a forward-looking agenda focusing around trade and the peace dividend that will ensue.

In a sign of paradigm shift, Zardari invoked the "India-China" model for bilateral ties, which entails focusing on scaling up trade while resolving more complex outstanding issues like Kashmir in a step-by-step incremental fashion.

Manmohan Singh acknowledged that Pakistan was moving forward on trade issues - a reference to Islamabad's movement in the direction of granting New Delhi the Most Favoured Nation status - as both leaders agreed to tap economic potential for trade and investment and broaden economic agenda between the two countries.

In a step forward, the two leaders directed their home secretaries to discuss the issue of terror and sign a pact on easing the visa regime.

After a warm handshake and clasp and smiles for the media, the two leaders sat down for talks, which Manmohan Singh said were "very constructive and friendly."

Manmohan Singh surprised many when he announced, at a joint appearance with Zardari, that he would be "very happy" to visit Pakistan, the most positive indication so far that the Pakistan-born Indian prime minister could after all go on his maiden visit to the neighbouring country.

"President Zardari has also invited me to visit Pakistan … I would be very happy to visit Pakistan on a mutually convenient date," said Manmohan Singh, who was born in the village in Gah in Pakistani Punjab.

If the visit takes place, it will be the first by an Indian prime minister to Pakistan in the last eight years. Atal Bihari Vajpayee was the last Indian prime minister to visit Pakistan in 2004.

Foreign Secretary Ranjan Mathai, briefing reporters later, said: "Terrorism is a major issue by which people will India will judge the dialogue process.

"This will be factored into when deciding the timing of the visit," an official elaborated.

The prime minister raised the issue of terrorism and conveyed to the Pakistan president that it "was imperative that perpetrators of the 26/11 Mumbai terror attack be brought to justice," Mathai said.

Responding to India's concerns, Zardari said that Pakistan is as much a victim of terrorism as India and said that there "were some legal issues" on the Pakistani side.

"The relation between India and Pakistan should become normal, that's our common desire," Manmohan Singh said. He stressed that the two sides were "willing to find practical, pragmatic solutions" to all issues dogging their ties "and that's the message that President Zardari and I would wish to convey."

Greeting the Indian people with a "Salaam Walaykum," a beaming Zardari stressed that India and Pakistan are neighbours and "we will like to have better relations with India".

"We have spoken about every issue we could have spoken about," Zardari, who was dressed nattily in a black suit with a red tie, said. Manmohan Singh was dressed in his usual kurta-churidar and a grey Nehru jacket.

Zardari said he hoped to see Manmohan Singh on Pakistan soil soon. His son Bilawal, dressed in a black pathani suit, was standing behind him as Zardari addressed the media.

Manmohan Singh was invited to visit Pakistan by Prime Minister Yousaf Raza Gilani on the sidelines of the Nuclear Security Summit in Seoul March 27, and had replied that he would visit only if something "solid" was achievable.

Although no timeline has been set for the visit, government sources indicated that there was a strong possibility of Manmohan Singh visiting Pakistan, but added caveats that the timing will depend upon Islamabad's actions on 26/11 justice and the progress in resolving issues like Sir Creek on India's western border and further movement on trade.

In a step forward, sources indicated that issues like the disputed marshland are doable and a resolution of this issue could form the substantial outcome that could be flaunted as a showpiece during Manmohan Singh's likely visit.

Pakistan has been pressing India for long to resolve doable issues like Siachen and Sir Creek, but India had said more time was required. Sources, however, Sunday indicated that Sir Creek could be resolved, while Siachen may take some more time.

Enjoyed lunch with Rahul and PM: tweets Bilawal Bhutto

Bilawal Bhutto, the 24-year-old son of Pakistan President Asif Ali Zardari who came to India Sunday on his maiden visit, said he enjoyed lunch with Prime Minister Manmohan Singh and Congress general secretary Rahul Gandhi and that both the countries can learn a lot from each other.

An avid tweeter like most young people Bilawal, shortly after landing in New Delhi, tweeted peace greetings for India.

"India Peace be with you. I have just landed in Delhi. 1st ever visit," Bilawal said on micro-blogging site twitter, a little while after his aircraft touched down at Palam airport at noon.

As soon as he landed in Jaipur, before heading for Ajmer, Bilawal tweeted his appreciation of the lunch.

"Prez n I enjoyed lunch with Rahul Gandhi and PM Singh. Lovely meal. Much to learn from each other," he said.

Bilawal, dressed in a black pathani suit, was seen standing behind his father as Zardari and Prime Minister Manmohan Singh addressed the media after their talks.

Bilawal accompanied his father and other members of the Pakistani delegation for lunch at Prime Minister Manmohan Singh's 7, Race Course Road, residence.

After the lunch meeting, President Zardari headed for Ajmer to offer prayers at the shrine of Sufi saint Khwaja Moinuddin Chisti.