Ljungberg made the announcement through a letter released via the website of Swedish newspaper Helsingborg Dagbladet.

"The simple fact is the physical strain of playing on the national team and in club football for such a long time has finally taken its toll," Ljungberg wrote.

"And that is why I have decided to concentrate on playing for West Ham United and that is where my focus will be."

Ljungberg, 31, has been part of the Sweden team for the last decade and his international career reached a new high when he was handed the captain's armband ahead of Euro 2008.

However, an ageing Sweden team made their exit at the group stage after recording only one win - over reigning champions Greece - in Group D.

"I can honestly say that I have loved every match, especially the outstanding support that you the fans have always given us players," Ljungberg added.

"I will carry on playing football at the highest level in the Premier League for several more years and I love this sport more than anything."

Ljungberg earned 75 caps and scored 14 goals for his country.

He joined West Ham prior to the start of last season after spending nine trophy-laden years at London rivals Arsenal.

He has suffered a number of injuries recently and saw his Premier League season ended early due to a broken rib sustained against Newcastle in April.

He has three years left on his contract with West Ham.