Once seen as one of America's strongest allies in the volatile Central Asian region near Afghanistan, President Karimov has become one of the world's most isolated rulers due to his heavy-handed response to protests and Islamic opponents.
The Organization for Security and Co-operation in Europe, which monitored the election, said the election had been "held in a strictly controlled political environment, leaving no room for real opposition".
"The election generally failed to meet many OSCE commitments for democratic elections," the organization's statement read.
Observers from Russia, a longtime ally of Karimov's, dismissed the European criticism, saying they had not seen any irregularities.
The election "proceeded in line with the country's election legislation and universally recognized norms for holding democratic elections," mission head Sergei Lebedev was quoted as saying by the ITAR-Tass news agency. "It was a major factor in further democratization of social life in Uzbekistan."
For Karimov, who has banned independent media and large-scale opposition parties throughout his 17-year rule, it was the first election since his bloody crackdown on protests in 2005.
During those protests, Karimov deployed thousands of troops to crush a revolt in a border town in eastern Uzbekistan, saying it was fomented by Islamic terrorists. Activists said more than 700 civilians, including many children, died in the operation.
Karimov said only 189 Islamic terrorists died in the violence and blamed the extremists for promoting "hatred and aversion to the secular path of development".
Analysts at the time said Uzbekistan's crackdown posed a major policy challenge to the United States in particular.
"Uzbekistan exemplifies the challenge that the U.S. faces, which is maintaining anti-terror cooperation, while also advancing reforms," Daniel Kimmage, a central Asian analyst at Radio Free Europe/Radio Liberty, told the NewsHour. "Uzbekistan played an important part in allowing the U.S. to support operations in Afghanistan, and at the same time of course there is now a great deal of pressure to work toward democratization."
In the wake of the crackdown, American policymakers distanced themselves from Karimov. But both China and Russia have remained close with the government of the oil-rich Central Asian republic.
Karimov, who will turn 70 next month, became the top Communist boss in 1989 in what was then a Soviet republic and Soviet industry's main cotton supplier. Since the Soviet collapse, he has won two presidential elections -- in 1991 and 1999 -- and had his term extended twice, once through parliament and again in a referendum.
None of those elections were recognized by international observers as free or fair.