Pakistan won't limit its nuclear programme, its UN envoy Maleeha Lodhi said on Wednesday, a day after Washington urged Islamabad to curtail its atomic activities.Lodhi told reporters here that such proposals of nuclear restraint should be first implemented by India before Pakistan does it. "Pakistan's nuclear programme cannot be limited," Lodhi said at the joint press conference with Foreign Secretary Aizaz Chaudhry."The world should first put an end to nuclear activities undertaken by India."The remarks came a day after US Secretary of State John Kerry urged Prime Minister Nawaz Sharif to limit Pakistan's atomic programme. US State Department spokesperson John Kirby said at a briefing on Tuesday that Kerry and Sharif discussed "our strong, long-term bilateral partnership and to build upon the US-Pakistan Strategic dialogue"."Kerry also stressed the need for restraint in nuclear weapon programmes. The secretary praised Pakistan for hosting the Afghan refugees for over 40 years and highlighted the importance of continued respect for humanitarian principles."