ISLAMABAD: Days after cancelling his visit to Turkey, Prime Minister Nawaz Sharif has also decided not to proceed to the United Kingdom to attend the Nato summit to be held on September 4 and 5 in the city of Cardiff, diplomatic sources said.

The cancellation comes in the wake of anti-government protests in Islamabad where thousands of protesters led by Imran Khan and Tahirul Qadri are holding sit-ins across the Red Zone and calling for the premier to resign.

The prime minister was invited to the summit by Nato Secretary General Anders Fogh Rasmussen but with the cancellation, Pakistan will now be represented at the forum by junior diplomats, sources said.

The political crisis in Islamabad also recently led to the cancellation of Sri Lankan President Mahinda Rajapaksa's visit to the capital and with the prevailing deadlock, concern prevails whether the Chinese President Xi Jinping will still be able to visit the capital this month.

This year's summit comes as Nato draws down from its longest ever mission in Afghanistan and against a backdrop of instability in Ukraine. US President Barack Obama, German Chancellor Angela Merkel and French President Francois Hollande are expected to attend along with leaders and senior ministers from around 60 other countries.