The Canadian government has proposed sweeping changes to its rules on citizenship.
Under the plans, Canada would be able to revoke citizenship from dual nationals who have been convicted of terrorism, spying or high treason.
Applicants would also have to pass a knowledge test and have proficiency in English or French.
Immigration Minister Chris Alexander said citizenship should not be simply a "passport of convenience".
A government statement said new measures targeted those with dual citizenship found to have "membership in an armed force or organised armed group engaged in armed conflict with Canada".
Citizenship could also be revoked for any dual nationals "convicted of terrorism, high treason, treason or spying offences".
Other proposals for new applicants include having to wait six years to apply for Canadian citizenship instead of the current four.
Would-be citizens would need to be physically present for four of the six years and declare an "intent to reside".
Currently they must establish legal residence for three of the four years but do not have to be physically present or intend to reside in Canada.
The proposals also include tougher penalties for immigration fraud.
However, the government also promises to streamline the process by tackling the current huge backlog of applications.
"Our government is strengthening the value of Canadian citizenship," said Mr Alexander in a statement.
"Canadians understand that citizenship should not be simply a passport of convenience. Citizenship is a pledge of mutual responsibility and a shared commitment to values rooted in our history," he added.
The largest source of new immigrants to Canada is Asia, led by China, the Philippines, India and Pakistan.