WASHINGTON (Reuters) - Reports of extrajudicial killings and domestic wiretapping in Colombia are troubling, but Bogota has made enough progress on human rights to receive the remainder of its 2009 U.S. military aid, the U.S. State Department said on Friday.

Colombia, the world's top cocaine exporter, has received more than $6 billion in mostly military and anti-narcotics aid from Washington since 2000 to help it battle drug traffickers and Marxist FARC guerrillas waging Latin America's oldest insurgency.

Under U.S. law a portion of the aid is withheld each year until the State Department certifies to Congress that Colombia is meeting requirements regarding human rights and paramilitary groups.

U.S. lawmakers placed the condition on the aid because of concerns about the increase in right-wing paramilitary activity and extrajudicial killings amid Colombian President Alvaro Uribe's drive to end the country's 45-year leftist insurgency.

"There is no question that improvement must be made in certain areas," State Department spokesman Ian Kelly said in a statement.

"However, the Colombian government has made significant efforts to increase the security of its people and to promote respect for human rights by its Armed Forces and has thereby met the certification criteria," he added.

The statement did not say how much additional funding would be released to Colombia.

Kelly voiced concern about extrajudicial killings of men and boys from the poor Bogota suburb of Soacha. Nineteen young men from the suburb were slain by troops who tried to pass the bodies off as dead rebels in the guerrilla war.

An investigation found the soldiers were trying to inflate the body count in order to win promotions and bonuses promised by officers trying to crush the insurgency.

Kelly said the armed forces and prosecutor general in Colombia were swift to take action, dismissing 45 service members and investigating 75 soldiers.

"However, the Soacha case is not an isolated incident and additional actions will require firm leadership by the armed forces to resolve and eliminate abuses," Kelly said.

He also expressed U.S. concern about allegations of domestic wiretapping and surveillance by the Department of Administrative Security, calling them "troubling and unacceptable."