BRUSSELS—Dutch Prime Minister Mark Rutte warned Tuesday that he would sign the European Union's broad trade and political agreement with Ukraine only if he received legally binding solutions that address concerns expressed by Dutch voters in an April referendum on the deal.

Dutch voters rejected the deal in that vote, in a campaign dominated as much by domestic opposition to the European Union as specific concerns about Ukraine.

The EU-Ukraine agreement is the centerpiece of European cooperation with Kiev since pro-Western forces took office in Ukraine in 2014. The refusal of former Ukrainian President Viktor Yanukovych to sign the deal sparked the mass protests that eventually swept him from office in early 2014.

The agreement lowers tariffs across a wide range of goods and includes various kinds of political and economic cooperation between the EU and Ukraine.

Mr. Rutte acknowledged it would be hard to find a compromise that offers solutions to Dutch voters' concerns without ripping up an agreement that provisionally took full effect Jan. 1. The agreement has already been ratified by 27 of the 28 EU member states, Ukraine and the European Parliament.

Mr. Rutte said he didn't have any specific proposal for how the binding guarantees could be made.

"It could be that we have to change the text, it could be that you can find a solution which will not involve a change in the text of the association agreement. I don't know yet," he said. Mr. Rutte said that if he can't "achieve" legally binding solutions "then we will not see. That's also clear."

Any change to the text of the agreement could force all other governments to ratify the deal once again. That could be an opening for Russia to block the agreement. Russia has fiercely opposed the pact, saying it would harm its economy and was designed to force Ukraine to choose between East and West.

Trade ties between Russia and Ukraine have plunged since early 2014, following Russia's annexation of Crimea and fighting in eastern Ukraine between Kiev and pro-Russian separatists.

Mr. Rutte discussed the issue with other EU leaders at a Brussels summit Tuesday evening. It is the first proper discussion of the issue since the Ukraine referendum April 6.

Mr. Rutte acknowledged that if the Dutch government is unable to sign the so-called Association Agreement with Ukraine, other EU member states may "in some way or another will continue or renegotiate something else of which the Netherlands is not part."

He said he doesn't think either of those are answers the 'no' camp in the Netherlands was trying to achieve.

While the 'no' vote succeeded, it only just overcame the 30% threshold needed for the referendum to take effect.

Pools after the vote showed that some 'no' voters opposed the deal because they thought it could open a pathway for Ukraine to achieve membership in the EU.

A Dutch refusal to sign the agreement would be a fresh blow to the government of Ukrainian President Petro Poroshenko. Kiev is already facing a delay in its bid to win visa free access for its citizens to the bloc because of opposition by some member states.

Viktoria Dendrinou in Brussels contributed to this article.

Write to Laurence Norman at laurence.norman@wsj.com

(END) Dow Jones Newswires

June 28, 2016 20:45 ET (00:45 GMT)