OTTAWA (Reuters) - The head of a Canadian political party said on Thursday that an intelligence report about some members of parliament acting as agents for other nations was concerning and that offending lawmakers must be removed.

Prime Minister Justin Trudeau has been on the defensive since a committee of lawmakers that focuses on security matters said in a heavily redacted report this month that some elected officials had been "witting or semi-witting" participants in foreign interference operations.

"I am more alarmed today than I was yesterday," Jagmeet Singh of the opposition left-leaning New Democrats said on Thursday, after reading an unredacted version of that report.

Singh, who as the leader of a major party exercised his right to request increased security clearance to read the documents, said the report showed Canada is vulnerable to foreign interference and weakened the confidence of citizens.

"If there continues to be no consequences for MPs who knowingly help foreign governments act against Canadian interests, we will continue to be an easy target," Singh said.

"Removing MPs who knowingly participate in foreign interference would have the deterring effect on this type of behavior," he added

In the report, which was based on information from intelligence agencies, the committee of parliamentarians did not reveal any names but said India and China were the main foreign threats to Canada's democratic institutions.

Singh did not name any lawmakers either, or say how many were named in the report or if any them were sitting MPs, but he added that the report gave him "no reason" to remove any members of his own party.

Ministers have said naming legislators would break the law and that it would be up to police to investigate.

On Monday, the Trudeau-led Liberal government, facing accusations it is soft on security, bowed to opposition demands to refer the matter to a special inquiry underway to assess allegations of foreign interference in last two Canadian elections.

The special inquiry, in an interim report, last month announced it had found evidence of foreign interference in those federal elections but said the results of the votes were not affected and the electoral system was robust.

Canada's main spy agency last month said persistent Chinese election meddling had the potential to undermine Canadian democracy. Beijing routinely denies accusations of interference.

(Reporting by David Ljunggren and Ismail Shakil; Editing by Bill Berkrot)