Europe's antitrust chief hit back on Friday at media reports suggesting that he had bowed to political lobbying by delaying a final decision on alleged anti-competitive behavior by Google.

European Competition Commissioner Joaquin Almunia said in May that he wanted to close the case against the world's most popular internet search engine before the end of his five-year term, but he announced this week that he would not be able to do so before he stands down next month, leaving his successor to take over.

Almunia had previously indicated that he intended to accept concessions offered by the company in February in a proposed deal that attracted heavy criticism from rivals such as Microsoft, a host of smaller competitors across Europe and some EU lawmakers.

Speaking at a conference in New York on Friday, Almunia defended the delay by insisting that Google, under fire for allegedly promoting its own services at rivals' expense, needs to improve its proposal to settle the investigation without a fine, which could be as high as $5 billion.

"This case has generated many opinions, letters, statements, even campaigns," he said. "However, the only arguments we have taken into account were those included in the complainants' answers whenever they challenged the adequacy of Google's proposals."

Almunia also said he had not set a deadline for his decision, in contrast to his comments in May. "I have never linked the date of a decision to the duration of my mandate," he said.

Almunia will hand the case to his successor, former Danish economy minister Margrethe Vestager, who takes up her post in November. She will now have to decide whether to continue settlement talks with Google, charge the company or drop the case.