BRUSSELS — The European Union delayed a decision on whether to renew sanctions against Russia on Monday, after Italy insisted that more discussion was needed.

The failure to continue the sanctions for another six months indicates cracks in the bloc’s stance against Russian aggression in Ukraine. It could also push the issue to the agenda of a summit meeting of Europe’s leaders later this week.

The current sanctions do not expire until the end of January, and a decision to renew them is still expected, possibly in the next few days. Even so, the delay on Monday drew criticism from ministers favoring a tough and united line against Moscow, even at a time when the West is seeking Russian support in fighting Islamic State forces in Syria.

“I see no reason to delay,” said Linas Linkevicius, the foreign minister of Lithuania. He noted that a cease-fire, known as the Minsk agreement, between the Ukrainian government and Russian-backed separatist rebels had not yet been fully carried out.