The Israeli dance group whose appearance at the Edinburgh International Festival is at the centre of boycott calls, has expressed sadness at the "violent" attempt to stop its work being seen.

It comes as 200 demonstrators gathered at the Playhouse where the Batsheva Dance Company opened their show Hora last night. One member of the audience said the performance was disrupted three times by protesters who managed to get through a bag search with placards and a Palestinian flag.

She said: "On each occasion, the performers paused and the stage lights were dimmed while Playhouse staff in black T-shirts ushered the protesters out. The audience clapped loudly for the dancers during the disturbances. Israeli dignitaries were taken to a private box."

Earlier this week, leading writers including Iain Banks and Scotland's national poet, Liz Lochhead, signed a letter calling for the group to be barred from taking part in the festival.

Dina Aldor, executive director of the company, said they accepted the protest against them outside the venue – except when it disrupted the performance. But she described calls for a boycott of the contemporary dance company's work as a "violent act" and expressed surprise that artists would call for the cancelling of other artists' work.

She said: "We welcome any form of expression and diverse opinions, even though we don't agree with the content of them. But the idea of a boycott is a very violent act, whether it is against artists or any human beings, particularly because artists' work is a platform for dialogue.

"We are supportive of the idea of demonstrations and we are supportive of the voicing of opposition, but calling for a boycott is not about that.

"I am surprised artists supported [the letter calling for a boycott], there is a enough censorship and attempts to censor artistic expression in the world."

The letter, also signed by Tom Leonard, AL Kennedy and Raja Shehadeh, called for Batsheva Dance Company's invitation to the festival to be withdrawn by artistic director Jonathan Mills.

The letter said the company can be seen as being ambassadors for the Israeli state which "suffocates the livelihoods of Palestinian communities, including the right to cultural expression".

The Batsheva Dance Company and its junior company has 40 dancers drawn from Israel and abroad and tours extensively, with 250 shows annually. It was founded as a company in 1964 by the Baroness de Rothschild.

The company is funded by the Ministry of Culture and Sport and the city of Tel Aviv.

It performed at the Edinburgh Festival in 2008, and its current show is co-produced by the Montpellier dance festival and the Lincoln Center Festival of New York.

Ms Aldor said the company, which is not an official national company, does not endorse any political position. She added: "We do not support any government policy, whether it is this government [of Israel] or any other government.

"Would British artists like to be thought of supporting the British Government? What would they think of a boycott of British artists because of the Iraq war, for example?

"We respect different views but a boycott is taking it too far."

Ms Aldor said the group was grateful for the festival's support of its work.