def determine_block_positions(lines, block_start_marker, block_end_marker):
    """Determine the line indices of a block in a list of lines indicated by a given start and end marker.

    :param lines: list of strings
    :param block_start_marker: string marking the beginning of the block
    :param block_end_marker: string marking the end of the block
    :return: tuple of two integers representing the line indices that indicate the start and end of the block
    """
    block_start_index = -1
    block_end_index = -1

    for line_number, line in enumerate(lines):
        if block_start_marker in line:
            block_start_index = line_number + 1

        if block_end_marker in line:
            block_end_index = line_number
            break

    if block_start_index < 0 or block_end_index < 0:
        raise RuntimeError('failed to determine the starting or end point of the block')

    return block_start_index, block_end_index