Ahead of the ballot, the leaders of the main political groups at the Parliament said the European Union had to stand by its humanitarian values and ensure that Turkey did not reinstate the death penalty, which Mr. Erdogan has vowed to approve. A ban on capital punishment is a condition of European Union membership.

Some of the lawmakers said the European Union should not allow itself to be held hostage by Turkey over migration and should instead find ways to share the burden of looking after the influx. “The Turkey deal is an instrument we have given to Erdogan against us,” Ska Keller, a German lawmaker, told the Parliament this week.

A formal, binding procedure to suspend the Turkish accession talks has not been invoked by the vote.

For that to happen, the European Commission or one-third of European Union member states would first need to make a formal proposal to do so, and a majority of the member states would then have to vote in favor of the measure for it to pass. Turkey would also be granted the opportunity to be heard, according to rules established in 2005.

So far, European Union governments seem unwilling to go that far. Only Austria has publicly advocated suspending the talks.

Turkey first applied for membership in 1987, and formal negotiations began 11 years ago. But talks soon bogged down amid resistance from France and Germany, as well as vehement opposition from Cyprus, which is a member of the European Union but has been divided since Turkey invaded the north of the island in 1974.

The latest round of talks on Turkey’s joining the European Union has been underway for nine months.

Facing enormous pressure from migration, which had reached such levels that it was threatening to tear the bloc apart, the 28 member states agreed in March to speed up the discussions as one of several inducements to Turkey to quell the flow.