"In the circumstances I do not consider it possible to continue working as defence minister," Margus Hanson said, cited by his Reform party.

He said that while he had not intentionally broken a law on state secrets, he should not have had the documents at home.

A spokesman for Prime Minister Juhan Parts's office said the premier would accept the resignation later Wednesday on his return from a trip to Germany.

The burglar, who broke into Hanson's home over a week ago, stole his case, wallet and documents while the minister was asleep on an upper floor.

Police are still searching for the culprit, but state security police have launched a criminal probe into the circumstances.

There has been no official word on what the documents were about, but press reports say they included a detailed review of the weaponry of an army unit as well as papers about a possible weapons purchase from a Scandinavian country.

Estonia joined NATO in March of this year and became a member of the EU in May.

"I could not foresee there would be burglars in my house," Hanson said.

He went on: "As a rule, I don't take work-related information home, but my tight schedule lately unfortunately did not allow me to abide by this rule.

"But stepping down in this situation is suitable for the minister of a NATO country."

He said the public scrutiny following the burglary would hamper his work if he stayed in his post.

The Reform party said it had yet to decide who to nominate to replace him.

Hanson only revealed the theft late Monday, filing an application with the security police about the incident.