Timeline - The unravelling of ties between North Korea and Malaysia

North Korea barred Malaysians from leaving the country on Tuesday, sparking tit-for-tat action by Malaysia, as police investigating the murder of Kim Jong Nam in Kuala Lumpur sought to question three men hiding in the North Korean embassy.

Following is a chronology of ties between the two countries.

1973 - Malaysia and North Korea establish diplomatic ties.

1995 - Malaysia hosts talks between the United States and North Korea over freezing North Korea's nuclear programme.

2000 - Malaysia allows North Koreans to visit without visas.

2009 - Malaysia becomes first country whose citizens are allowed to travel to North Korea without a visa.

2011 - North Korea's state airline, Air Koryo, opens a route to Malaysia to attract more tourists.

2013 - Malaysia's HELP university confers an honorary doctorate degree on North Korea Leader Kim Jong Un.

READ: Malaysia-North Korea diplomatic row escalates to standoff

Feb 13 - North Korean leader Kim Jong Un's half-brother, Kim Jong Nam, is murdered at Kuala Lumpur International Airport.

Feb 15 - U.S. government believes North Korean agents were behind the murder, U.S. government source says.

Feb 15 - China had been protecting Kim Jong Nam, according to South Korea's spy agency.

Feb 15 - North Korea's leader had "standing order" to kill Kim Jong Nam, South Korean lawmaker says quoting Seoul's intelligence agency.

Feb 16 - Malaysian police arrest Vietnamese and Indonesian women in murder case.

Feb 19 - Malaysian police say four North Korean suspects left the country the same day of the murder.

Feb 20 - North Korean ambassador says Malaysia trying to delay release of victim's body for "political aim", says police investigation cannot be trusted.

Feb 22 - Malaysia identifies North Korean embassy official, employee of state airline among suspects.

Feb 22- Malaysia says no family members of Kim Jong Nam have come forward to identify body or give DNA samples.

Feb 23 - North Korea blames Malaysia, South Korea for death of one of its citizens.

Feb 24 - Police say VX nerve agent, a chemical the U.N. classifies as a weapon of mass destruction, was used to assassinate Kim Jong Nam.

Feb 26 - Malaysia declares Kuala Lumpur International Airport a "safe zone" after completing decontamination sweep.

Feb 27 - South Korean lawmaker says airport assassins were from North Korea's ministry of state security and the foreign ministry.

March 1 - Malaysia charges Indonesian and Vietnamese with Kim Jong Nam's murder.

March 2 - North Korea says heart attack likely killed airport victim.

March 4 - Malaysia rejects suggestions it may have violated U.N. sanctions after a Reuters report said North Korea-linked firms were running an arms network in the country.

March 4 - Malaysia deports North Korean suspect in Kim Jong Un's murder, saying it had insufficient evidence to charge him.

March 6 - Malaysia cancels visa waiver programme.

March 6 - Malaysia expels North Korean ambassador Kang Chol.

March 6 - Malaysia asks that an Asian Cup football qualifier against North Korea be moved from Pyongyang to a neutral venue.