He indicated that the charges may have arisen due to misunderstanding or misinterpretation.
He could face up to 25 years in prison if convicted. The judge said that he will decide on Monday whether Erlinder will be granted bail.
Erlinder was arrested on May 28, several days after flying into Rwanda to defend Victoire Ingabire, a presidential candidate in the country's upcoming August 9 elections.
"It is the first time I have come to know that my obscure publications back in America ... could amount to genocide denial"
Peter Erlinder, US lawyer
Ingabire was arrested in April on charges of promoting genocide ideology, and later released on bail.
Erlinder is the head of a group of defence lawyers at the UN's International Criminal Tribunal for Rwanda (ICTR) that is trying suspected leaders of the 1994 genocide in which an estimated 800,000 people, mostly Tutsis and moderate Hutus, died.
He is defending a suspected genocide mastermind at the ICTR and has previously accused its prosecution of hiding the crimes committed by the Rwandan Patriotic Front, led by Paul Kagame, the incumbent president.
Kagame headed the group of mostly Tutsi fighters to defeat mostly Hutus fighters behind the slayings.
Erlinder has requested bail to return to the US and receive treatment for injuries.
He asserted that he had not been maltreated in prison but had also not had contact with another person including family members and his doctor.
He said that he would comply with any bail conditions.
On Tuesday, Erlinder was hospitalised after police said he had attempted suicide by taking dozens of pills. However, Erlinder's family has disputed the suicide attempt claim.
On Thursday, the US called for Erlinder to be released on compassionate and humanitarian grounds.
"We are pressing the Rwandan government to resolve this case quickly, and we would like to see him released on compassionate grounds," Philip Crowley, a state department spokesman, said.