In an emergency hearing on Monday, India had accused Pakistan of "egregious violations of the Vienna convention" by denying Mr Jadhav, a former navy officer, of legal counsel and consular access and refusing to reveal the charges or evidence against him.
The ICJ said the mere fact that he may be executed is sufficient to demonstrate that there is a risk of irreparable damage and directed Pakistan to take all appropriate measures at its disposal to ensure Jadhav is not executed pending final decision.
Meanwhile, Pakistan Attorney General's Office said the ICJ has just maintained status quo in the case and Islamabad is determined to pursue this case to its logical end.
The Pakistan Tehreek-e-Insaf has submitted a resolution in Punjab Assembly against the stay of International Court of Justice in an Indian spy's case. Responding to the criticism by opposition parties, he said Pakistan could not have abstained from the hearing as any such move would have given advantage to India.
"The government of India must use the ICJ decision as a trigger to bring Kulbhushan Jadhav back".
"The real face of India will be exposed before the world", he said, adding that Jadhav has confessed his crimes of sabotage, terrorism and subversion activities not once but twice.More news: Comey Agrees To Testify Before Senate Intel Committee
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In its ruling, which was read out by the president of the United Nations court, Ronny Abraham asked Pakistan to give consular access to Jadhav, rejecting Pakistan's argument that a person convicted of espionage is not entitled to it. The court order was not legally binding in the U.S.
"Court considers it a failure on the part of Pakistan to present counselors to Jhadav", said President Ronny Abraham who announced the verdict.
The ICJ held that consular access is a right and Pakistan should have accorded the same to India.
Over the coming months, the court said, it would hear both countries' arguments on whether Indian diplomats should be allowed to visit Jadhav before issuing a verdict.
"This is a unanimous decision of the highest court, there is no unambiguity in this judgement". While not commenting specifically on the order to halt the execution, the office said in a statement that Jadhav "still has ample time to petition for clemency".
"In our submissions on 15 May, we had assured the Court unambiguously that Commander Jadhav would be provided every opportunity and remedy available under the law to defend his case".