WASHINGTON - Pakistani diplomats in the US could face travel restrictions similar to those imposed on American diplomats in Pakistan unless Islamabad lifts its curbs, according to US officials. 'Reciprocity is always a consideration, State Department spokesman Mark Toner remarked at a news briefing when specifically asked whether the US would slap tit-for-tat restrictions on Pakistani diplomats here. He said the US and Pakistan were working to end the spat, the latest irritant in already strained ties, and it was confident the dispute would be resolved quickly. But the officials, who were named in media reports, said Pakistan had been told that the Obama administration would consider reciprocal steps to retaliate for the restrictions set down last month by Pakistans Foreign Ministry if they are not rescinded. Toner declined to comment on the warning. 'We are working with the government of Pakistan to resolve the issue, Toner told reporters. 'Weve met with Pakistani officials on this matter both in Washington and in Islamabad, and we believe it can be resolved. The issue is the right of our diplomats to travel freely, he added. 'There was an incident last week, I believe, where diplomats were prevented from travelling between Islamabad and Peshawar, the spokesman said. 'We obviously raised our concerns. We feel that were making progress towards resolving the issue, Toner added. He said that diplomats were later able to travel between the Pakistani capital and Peshawar with a No-Objection Certificate, although he insisted the envoys should be able to travel freely in line with the Vienna Convention. 'Were working with the government of Pakistan to resolve the issue, he said. The spokesman also said the Pakistani authorities asked Cameron Munter, the US Ambassador to Pakistan, to produce a certificate of permission to travel before boarding a plane to Karachi. He did not have one, but was allowed to travel there anyway, Toner said without specifying whether it amounted to a diplomatic incident.He declined to rule out US authorities imposing travel restrictions on Pakistani diplomats.