State Department spokesperson Mathew Miller said that the US was closely following actions taken against opposition parties in India.
Miller's remarks came hours after India summoned a US diplomat over a similar comment he made earlier.
Kejriwal, who was arrested last week, has denied any wrongdoing.
Hours before his arrest, India's main opposition Congress party had held a press conference saying that its bank accounts were frozen by the tax department ahead of the general elections.
Kejriwal's Aam Aadmi Party (AAP) and the Congress have accused the ruling Bharatiya Janata Party (BJP) government of political vendetta.
The BJP denies the allegation, saying investigative agencies were doing their work independently.
Miller told reporters that US was also aware of the Congress party's allegations that the freezing of their bank accounts would make it challenging to effectively campaign in the upcoming elections.
"We encourage fair, transparent, timely legal processes [in both cases]. We don't think anyone should object to that," he added.
India's foreign ministry had summoned US acting deputy chief of mission, Gloria Berbena, to protest against similar remarks by Miller.
India had also issued a statement saying that in diplomacy, states are expected to be respectful of the sovereignty and internal affairs of others.
"India's legal processes are based on an independent judiciary which is committed to objective and timely outcomes. Casting aspersions on that is unwarranted", the statement added.
The US is the second country to comment on Kejriwal's arrest. Last week, the German foreign ministry said it hoped that Kejriwal would get a fair and impartial trial as India is a democratic nation.
India reacted strongly to these remarks as well and summoned a German diplomat to raise its objections.
Indian opposition leaders have accused Prime Minister Narendra Modi's BJP of using investigative agencies to cripple their parties and stifle dissent before the elections.
In January, the Enforcement Directorate (ED — India's financial crimes agency) arrested top opposition leader Hemant Soren in a corruption case, hours after he resigned from the position of the chief minister of Jharkhand state.
Soren and his party denied any wrongdoing and accused the BJP of stifling opposition. The BJP has rejected his claim.
Amnesty International has also said that that the crackdown on peaceful dissent and opposition in India has now reached a crisis point.
Kejriwal is the third AAP leader to be arrested over the alleged corruption case related to a now-scrapped liquor policy in Delhi.
The BJP has alleged that the policy — which ended the government's monopoly on alcohol sales — gave undue advantages to private retailers.
The ED has accused AAP leaders of receiving kickbacks to be used in state elections. The party denies the allegation.
