By Oana Lungescu BBC correspondent in Brussels

Poland has pledged to hire thousands more border guards and tighten immigration controls before it joins the European Union.

The commitments allowed it to conclude talks with the EU on the sensitive issue of justice and home affairs and stay on track to wrap up entry negotiations in December, along with nine other applicant countries.

But there are renewed warnings about difficulties ahead.

Many in the European Union fear that eastward expansion will bring more illegal immigrants and higher crime levels.

To reassure them, the biggest candidate country, Poland, plans to hire more than 5,000 border guards by 2006 - 50% more than at present.

Most of them will replace conscripts currently patrolling Poland's 1,200 kilometre (745 mile) border with Ukraine, Russia and Belarus.

Visas for neighbours

There are also plans to build new border stations and buy modern equipment such as helicopters.

To fall into line with EU requirements, Poland will also introduce visas for Russians, Ukrainians and Belarussians in less than a year's time.

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With one million visas expected to be delivered every year, a Polish senior official said new visa offices would be opening in the autumn.

The first will be in the Russian enclave of Kaliningrad, which will be cut off from mainland Russia once Poland and Lithuania join the EU.

Visa fees will be set as low as possible, a border guard said.

"It is not in our interest to make the life of our neighbours unnecessarily complicated," he said.

Having concluded talks on this sensitive area, Poland hopes to be one of the 10 countries expected to wrap up EU entry negotiations in December.

But there are no guarantees.

Voter rejection

By late October, EU governments have to agree on how much aid to grant to farmers and poor regions in eastern Europe.

If there is no unanimous agreement, a senior EU official warned, there will be delays.

There are also fears that, at around the same time, Irish voters may reject for a second time the Treaty of Nice, which paves the way for expansion.

If that happens, according to a senior diplomat, we will enter extremely complicated waters and the result is impossible to predict.