Indian Prime Minister Narendra Modi has landed in Pakistan on a surprise visit in which he will meet his Pakistani counterpart Nawaz Sharif.

Modi was on his way back to India from Afghanistan when he stopped off in the eastern city of Lahore. The visit coincides with Sharif's birthday.

Modi is the first Indian PM to visit Pakistan since 2004.

Tensions between the two nuclear-armed neighbours have been high in recent years but relations have begun to warm.

The pair met briefly in Paris last month on the sidelines of the COP21 climate change conference.

The two countries have fought three wars since independence from Britain in 1947, two of them over Kashmir.

Kashmir, claimed by both countries in its entirety, has been a flashpoint for more than 60 years.

A ceasefire agreed in 2003 remains in place, but the neighbours often accuse each other of violating it.