Malmo/Stockholm - Swedish police on Friday stepped up their presence around the arena due to host the Davis Cup tie between Sweden and Israel as the first group of demonstrators assembled.

The tie in the southern city of Malmo is been played behind closed doors.

It has been classified as a high-risk event over potential protests by groups wanting to protest against the recent Israeli offensive against Hamas in Gaza.

Former Swedish great Mats Wilander and Isreal team member Andy Ram were among those critical of the decision by Malmo's city council.

Supporters of the Swedish section of the pro-Palestinian group International Solidarity Movement were among the first to gather Friday morning near the Baltic Hall arena.

Some 20 demonstrators unfurled banners and a Palestinian flag, and a few played an improvised tennis match with toy plastic rackets.

Two perimeter fences have been erected around the arena, and a nearby school and a Pentecostal church were closed Friday.

Later Friday - when the first singles match was due - the militant leftist group Anti-Fascict Action (AFA) has called for a protest.

Last month, Malmo city council's board for leisure, recreation and sport activities voted that the tie would be played behind closed doors, citing security concerns.

The move came in the wake of anti-Isreal protests during a match of Israel player Shahar Peer at a tournament in Auckland. peer was later given no visa for a tournament in Dubai, but Ram played there a week later.

Some 1,000 police officers were reported to be on duty, although Malmo police spokesmen declined to specify exact numbers.

Hakan Jarborg Eriksson, head of the police force at the event, told public broadcaster SVT there was "an imminent threat" that some groups could try to cause trouble but was confident the police could cope.

Specially reinforced police vehicles used by police in neighbouring Denmark were on standby along with a vehicle equipped with a scoop in order to remove torched cars or other debris.

On Saturday, the umbrella group, Stop the Match, hopes to assemble some 8,000 people. Olof Holmgren, one of the group's founders, has told reporters that 100 marshals were to be posted along the route of the march and would also ban masked demonstrators. (dpa)