The United States is concerned over the intimidation of candidates and voters by Pakistani intelligence agents, a media report said on Thursday, warning that the practice could not only seriously discredit the February election's outcome, but lead to new instability in the Islamic state.

"With just 18 days until a pivotal election, the United States is pressing Pakistan to help end the intimidation of candidates and voters by intelligence officers and local government officials, which could discredit the election's outcome and provoke new instability," the influential Washington Post reported, quoting American and Pakistani sources.

The report based on feedbacks from US and Pakistani officials said interference by local and intelligence officials has become the biggest pre-election problem, affecting roughly two-thirds of the 272 districts.

"There have been violations of election rules throughout the process," said Muddassir Rizvi, national coordinator of the Free and Fair Election Network in Pakistan.

With US and Pakistani experts concerned that the election could be manipulated widely at the local level, the Bush administration has appealed to the election commission in Islamabad to publish the results of each polling station to prevent rigging, the report said.

The US observer group, the International Republican Institute, which had earlier planned to monitor the crucial February 18 polls in Pakistan, canceled its mission over security concerns.

"We don't believe the security environment is such that we could do the things we'd like to do, such as spending time in polling stations and going out among voters. We felt it was too much exposure," Thomas E Garrett, the IRI election expert on Pakistan was quoted as saying by the paper.

The report said the delicate law and order problem will ensure that presence of international monitors will be minimal -- "limited to about 100 observers from the European Union, a few foreign politicians, plus small teams pulled together from embassies in Islamabad".

Even Pakistani observers are facing "an array of problems just getting accredited," report said.