The US State Department has authorised the families of diplomatic personnel based in northern Mexico to leave the country after the murder of two Americans connected with the consulate in the city of Ciudad Juarez.
On Saturday an American woman working at the consulate and her US husband were shot dead by suspected drug gang hitmen in broad daylight as they left a consulate social event.
The couple's baby girl, who was in the car with them, survived the attack.
Around the same time a Mexican man married to another consulate employee was killed in another part of the city after he and his wife left the same event.
The killings were among dozens over the past two days, as rival Mexican drug gangs fight for turf with civilians caught in the middle.
A US official, who asked not to be identified, told the Reuters news agency it was not clear if the victims had been specifically targeted.
A spokesman for the US president, Barack Obama, said he was "saddened and outraged" by the killings.
'Growing tragedy'
Meanwhile the US state department said it had updated travel warnings to the area and authorised the departure of dependents of consular staff.
"These appalling assaults on members of our own State Department family are, sadly, part of a growing tragedy besetting many communities in Mexico," Hillary Clinton, the US Secretary of State, said in a statement on Sunday.
Nearly 19,000 people have been killed in drug-related violence since late 2006 when Felipe Calderon came to power as Mexico's president and launched a military assault on the country's powerful drug cartels.
Mexican authorities say they have launched a full investigation into Saturday's killings.
"The Mexican authorities are determined to clarify what happened and bring those responsible to justice," the Mexican foreign ministry said in a statement.
Beheaded
Across Mexico, drug-related violence has reached record levels with at least 27 people over the weekend around the Pacific resort city of Acapulco.
Four of the dead were beheaded.
According to police at least 13 people died on Saturday and at least another 14 on
Sunday.
The victims included nine men killed in a shootout and a young woman shot as she drove by in a taxi.
On Saturday an American woman working at the consulate and her US husband were shot dead by suspected drug gang hitmen in broad daylight as they left a consulate social event.
The couple's baby girl, who was in the car with them, survived the attack.
Around the same time a Mexican man married to another consulate employee was killed in another part of the city after he and his wife left the same event.
The killings were among dozens over the past two days, as rival Mexican drug gangs fight for turf with civilians caught in the middle.
A US official, who asked not to be identified, told the Reuters news agency it was not clear if the victims had been specifically targeted.
A spokesman for the US president, Barack Obama, said he was "saddened and outraged" by the killings.
'Growing tragedy'
Meanwhile the US state department said it had updated travel warnings to the area and authorised the departure of dependents of consular staff.
"These appalling assaults on members of our own State Department family are, sadly, part of a growing tragedy besetting many communities in Mexico," Hillary Clinton, the US Secretary of State, said in a statement on Sunday.
Nearly 19,000 people have been killed in drug-related violence since late 2006 when Felipe Calderon came to power as Mexico's president and launched a military assault on the country's powerful drug cartels.
Mexican authorities say they have launched a full investigation into Saturday's killings.
"The Mexican authorities are determined to clarify what happened and bring those responsible to justice," the Mexican foreign ministry said in a statement.
Beheaded
Across Mexico, drug-related violence has reached record levels with at least 27 people over the weekend around the Pacific resort city of Acapulco.
Four of the dead were beheaded.
According to police at least 13 people died on Saturday and at least another 14 on
Sunday.
The victims included nine men killed in a shootout and a young woman shot as she drove by in a taxi.
