Service Broker Activated Procedure Getting Deadlock While Running Mulitple Queue_reader Threads

Hi,

I am getting deadlock on activated procedure which I am using to receive message from the Service Broker Queue.

Deadlock details:

Two threads are tring to do delete on internal table queue_messages_122847900 ends up in a dead lock.

Activated procedure code

RECEIVE TOP(1) @xmlMessage = message_body,
@handle = conversation_handle,
@message_type = message_type_name
FROM TransactionQueue;

IF (@message_type = 'http://schemas.microsoft.com/SQL/ServiceBroker/EndDialog')
BEGIN
END CONVERSATION @handle;
RETURN 0
END
.........................
.........................
After this I do process the message and some other processing

And then

END CONVERSATION @handle;

Note I do have single conversation group

Is their a problem in the way I am receiving and processing messages. Is it possible because of the delay between RECEIVE and END CONVERSATION same message is read by two different threads.

Thanks