Canada, the United States and Britain joined forces Friday to tighten travel sanctions on Iranian leaders suspected of human rights abuses or of links to Tehran's disputed nuclear program.

"Canada, the United Kingdom and the United States will coordinate to prevent Iranian human rights offenders or individuals connected with the nuclear program from entering our countries," Canadian Foreign Minister John Baird said.

"The message to the Iranian leadership is clear: Iran will not take its place as a full and respected member of the international community until its government meets its international and domestic obligations," he added.

Britain said scientists and engineers were among more than 50 people targeted by a visa restriction and ban, but said they would not be publishing any names saying in "some cases, the individuals have a range of identities."

"Iran continues to seek equipment and components from around the world for its illicit nuclear program," British Foreign Secretary William Hague said.

"The UK is working closely with its partners to prevent a wide range of individuals connected with Iran's nuclear enrichment and weaponization programs from entering our countries. These include scientists, engineers and those procuring components."

Western nations accuse Iran of seeking to develop an atomic weapon under the guise of its nuclear power energy program. Tehran has denied the charges saying that its nuclear program is for civilian purposes only.

The United Nations has already slapped a wide range of sanctions on the Islamic republic over its refusal to halt its uranium enrichment program.

US Secretary of State Hillary Clinton said the list of people targeted Friday included "government ministers, military and law enforcement officers, and judiciary and prison officials."

"Today's actions are an important reminder to Iran that the international community will continue to hold accountable those officials who commit human rights abuses and suppress the democratic aspirations of fellow citizens."

The State Department added the new restrictions would apply to "those who have played a role in the ongoing repression of students, human rights defenders, lawyers, artists, civil society representatives, women's rights leaders, and religious and ethnic minorities."